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Unit 4 Math 3200 1
x
y
Ter m inal Ar m
a I nit ial Ar m
Unit 4 Chapter 4
Trigonometry and the Unit Circle
41 Angles and Angle Measure
(I) Angles in Standard Position
Reference Angle
formed between the x-axis and
the terminal arm
Terminal Arm
can rotate clockwise (ndash rotation)
or counterclockwise (+ rotation)
Angle of Rotation
Goals
Angles in Standard Position
Angles Measured in Degrees and Radians
Converting between Degree and Radian Measure
Coterminal Angles
Solving Problems involving Arc Length
Unit 4 Math 3200 2
Example Sketch each angle in standard position
1 150deg 2 270deg 3 510deg
4 ndash210deg 5 ndash720deg
(II) Angles measured in Degrees and Radians
Degree Measure
Radian Measure
What is radian measure
One revolution is equivalent
to the circumference C = 2πr
If we consider the unit circle
Angles in Standard Position
-have center at the origin and
initial arm along the positive
x-axis
1 revolution = 360deg
Unit 4 Math 3200 3
where r = 1 then one revolution is equivalent to
Example Sketch each radian measure of rotation
1 2π radians 2 1π or π radians 3 1
2120587 119900119903
120587
2 119903119886119889119894119886119899119904
C = 2π(1) radians
= 2π radians
Therefore
2π radians = 1 revolution
Comparing Radian Measure to Degree Measure
1 revolution 2π radians = _______
1
2 revolution π radians = _______
Unit 4 Math 3200 4
(III) Converting Between Degree and Radian Measure
Example Change each degree measure to radians each radian
measure to degrees and sketch angle in standard
position
(a) 60deg (b) minus3120587
4
(c) 7120587
6 (d) ndash45
Unit 4 Math 3200 5
(IV) Determining the measure of angles that are
coterminal with a given angle
Sketch each angle below in standard position on the same grid
(a) 30deg (b) 750deg (c) ndash330deg
Example State one positive and one negative angle coterminal
with
(a) 210deg (b) minus7120587
5
Coterminal Angles
Angles in standard position that have the same _____________
Angles that are a multiple of ___________ away
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 2
Example Sketch each angle in standard position
1 150deg 2 270deg 3 510deg
4 ndash210deg 5 ndash720deg
(II) Angles measured in Degrees and Radians
Degree Measure
Radian Measure
What is radian measure
One revolution is equivalent
to the circumference C = 2πr
If we consider the unit circle
Angles in Standard Position
-have center at the origin and
initial arm along the positive
x-axis
1 revolution = 360deg
Unit 4 Math 3200 3
where r = 1 then one revolution is equivalent to
Example Sketch each radian measure of rotation
1 2π radians 2 1π or π radians 3 1
2120587 119900119903
120587
2 119903119886119889119894119886119899119904
C = 2π(1) radians
= 2π radians
Therefore
2π radians = 1 revolution
Comparing Radian Measure to Degree Measure
1 revolution 2π radians = _______
1
2 revolution π radians = _______
Unit 4 Math 3200 4
(III) Converting Between Degree and Radian Measure
Example Change each degree measure to radians each radian
measure to degrees and sketch angle in standard
position
(a) 60deg (b) minus3120587
4
(c) 7120587
6 (d) ndash45
Unit 4 Math 3200 5
(IV) Determining the measure of angles that are
coterminal with a given angle
Sketch each angle below in standard position on the same grid
(a) 30deg (b) 750deg (c) ndash330deg
Example State one positive and one negative angle coterminal
with
(a) 210deg (b) minus7120587
5
Coterminal Angles
Angles in standard position that have the same _____________
Angles that are a multiple of ___________ away
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 3
where r = 1 then one revolution is equivalent to
Example Sketch each radian measure of rotation
1 2π radians 2 1π or π radians 3 1
2120587 119900119903
120587
2 119903119886119889119894119886119899119904
C = 2π(1) radians
= 2π radians
Therefore
2π radians = 1 revolution
Comparing Radian Measure to Degree Measure
1 revolution 2π radians = _______
1
2 revolution π radians = _______
Unit 4 Math 3200 4
(III) Converting Between Degree and Radian Measure
Example Change each degree measure to radians each radian
measure to degrees and sketch angle in standard
position
(a) 60deg (b) minus3120587
4
(c) 7120587
6 (d) ndash45
Unit 4 Math 3200 5
(IV) Determining the measure of angles that are
coterminal with a given angle
Sketch each angle below in standard position on the same grid
(a) 30deg (b) 750deg (c) ndash330deg
Example State one positive and one negative angle coterminal
with
(a) 210deg (b) minus7120587
5
Coterminal Angles
Angles in standard position that have the same _____________
Angles that are a multiple of ___________ away
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 4
(III) Converting Between Degree and Radian Measure
Example Change each degree measure to radians each radian
measure to degrees and sketch angle in standard
position
(a) 60deg (b) minus3120587
4
(c) 7120587
6 (d) ndash45
Unit 4 Math 3200 5
(IV) Determining the measure of angles that are
coterminal with a given angle
Sketch each angle below in standard position on the same grid
(a) 30deg (b) 750deg (c) ndash330deg
Example State one positive and one negative angle coterminal
with
(a) 210deg (b) minus7120587
5
Coterminal Angles
Angles in standard position that have the same _____________
Angles that are a multiple of ___________ away
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 5
(IV) Determining the measure of angles that are
coterminal with a given angle
Sketch each angle below in standard position on the same grid
(a) 30deg (b) 750deg (c) ndash330deg
Example State one positive and one negative angle coterminal
with
(a) 210deg (b) minus7120587
5
Coterminal Angles
Angles in standard position that have the same _____________
Angles that are a multiple of ___________ away
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 6
Coterminal Angles in General Form
Example
Express each of the given angles in general form and state the angles
that are coterminal with the given angle that also satisfy the stated
domain
(a) 135deg domain ndash720deg le Ө le 720deg
(b) 5120587
6 domain ndash4π le Ө le 4π
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 7
(V) Solving Problems involving arc lengths central
angles and the radius in a circle
Arc Length of a Circle
All arcs that subtend the same central angle
have different arc lengths depending on the
radius of the circle The arc length is proportional
to the radius This is true for any central angle
and related arc length
Consider the circle with radius r and the sector with
central angle Ө
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
d
E
F
120579 = 119886119903119888 119897119890119899119892119905ℎ
119903119886119889119894119906119904
O
C
B
a θ
r
120579 = 119886
119903
Arc length of a circle
a =
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 8
Example
Determine arc length in a circle
Rosemarie is taking a course in industrial engineering
For an assignment she is designing the interface of
a DVD player In her plan she includes a decorative
arc below the onoff button The arc has central angle
130deg in a circle with radius 67 mm Determine the
length of the arc to the nearest tenth of a mm
Textbook Homework pg 175 1-9 12-14 16-17 21-23 C4
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 9
42 The Unit Circle
(I) The Unit Circle
The Unit Circle
Has center at the origin (0 0) and a radius length r = 1
Label the coordinates of the four terminal positions on the unit
circle below
x
y
Goals
The Unit Circle
Developing and Applying the Equation of the Unit Circle
Locating Coordinates of Points on the Unit Circle
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 10
(II) Developing and Applying the Equation of the
Unit Circle
Equation of a Circle Centered at the Origin
(a) Identify the radius of the circle
(b) Identify the coordinates of the point P
(c) Draw a vertical line segment PN from P to the x-axis
(d) Draw a horizontal line segment NO from N to the origin
(e) What type of triangle have you created
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 11
(f) Determine the lengths of PN and NO
(g) Write an equation that relates the three sides of the triangle
(h) Write an equation of any circle that is centered at the origin
and has a radius of lsquorrsquo
Example
Determine the equation of the circle with center at the origin and
(a) r = radic10 (b) diameter = 12 (c) passing through the
point (8 15)
Equation of a Circle Centered at the Origin
Any circle with its center at the origin O(0 0)
and radius lsquorrsquo is defined by the equation
________________
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 12
(III) Using Symmetry and Patterns to Locate the
Coordinates of Points on the Unit Circle
Example
Determine Coordinates for Points of the Unit Circle
(a) 119875 (1
5 119910)in quadrant 1
Remember The Unit Circle
Coordinates on the unit circle satisfy the
equation x2 + y2 = 1
x
y
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 13
Example
Determine Coordinates for Points of the Unit Circle
(b) 119875 (119909 minus3
8)
x
y
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 14
Relating Arc Length and Angle Measure in Radians
lsquoarsquo is the arc length
Ө is the central angle in radians
r is the radius (which is measured in the same units as lsquoarsquo)
In the unit circle (r = 1) the formula a = Өr
becomes a = Ө1
a = Ө
Arc length of a circle
a = Өr O
C
B
a θ
r
O
C
B
Ө
1
Ө
This means that the central angle
and the subtended arc on the unit
circle have the same numerical
value
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 15
Example Multiples of 120645
120785 on the Unit Circle
(a) On a diagram of the unit circle show the integral multiples
of π
3 in the interval 0 le Ө le 2π
(b) What are the coordinates for each point P(Ө) in part (a)
(c) Identify any patterns observed in the coordinates of the point
x
y
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 16
Note
You can see patterns to determine coordinates of points The
numerical value of the coordinates of points change sign
Some points on the unit circle correspond to exact values of special
angles (where reference angles equal 30deg 45deg and 60deg)
If P(a b) is in quadrant I then both lsquoarsquo and lsquobrsquo are positive P(Ө + π)
is in quadrant III Its coordinates are (ndasha ndashb) where a gt 0 and b gt 0
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 17
Example Determine the exact coordinates of the terminal arm
of angle Ө given P(Ө)
(a) 119875 (5120587
6) (b) 119875 (
3120587
2)
Example Identify the measure for the central angle Ө given in
the interval 0 le Ө lt 2π such that P(Ө) is the given
point
(a) (radic2
2 minus
radic2
2) (b) (
radic3
2 minus
1
2)
x
y
x
y
x
y
x
y
Textbook Homework pg 186 1-6 10-13 16
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 18
43 Trigonometric Ratios (Part I)
(I) Primary Trig Ratios and Coordinates of Points on Terminal Arm
If P(Ө) = (x y) is a point on the terminal arm of Ө then define the
coordinates of the point P(Ө) in terms of the primary ratios based
on the diagram below
Remember Primary Trig Ratios
SOHCAHTOA
sin 120579 = 119900119901119901
ℎ119910119901 sin 120579 =
cos 120579 = 119886119889119895
ℎ119910119901 cos 120579 =
From above we can see that
x = and y =
hence the point P(Ө) = (x y)
Can be expressed as P(Ө) =
Goals
Primary Trig Ratios amp Coordinates of Points on Terminal Arm
Reciprocal Trig Ratios
Determining Trig Ratios of Point on Terminal Arm amp
Determining Angle of Rotation
Exact Values of Trig Ratios
Approximate Values of Trig Ratios
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 19
From this we can also conclude that since tan 120579 = 119910
119909
then
(II) Reciprocal Trig Ratios
Coordinates of Point on Terminal Arm
Since x = and y =
Any point on the terminal arm of angle Ө
can be represented by P(Ө) = (cos Ө sin Ө)
tan Ө =
Each primary trig ratio has a reciprocal trig ratio
(i) sin 120579 = 119900119901119901
ℎ119910119901 cosecant Ө csc 120579 =
ℎ119910119901
119900119901119901=
1
119910=
1
sin 120579
(ii) cos 120579 = 119886119889119895
ℎ119910119901 secant Ө sec 120579 =
ℎ119910119901
119886119889119895=
1
119909=
1
cos 120579
(iii) tan 120579 = 119900119901119901
119886119889119895 cotangant Ө cot 120579 =
119886119889119895
119900119901119901=
119909
119910=
cos 120579
sin 120579
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 20
(III) Determining Trig Ratios Given a Point on the Terminal Arm
and Determining Angle of Rotation
Example Given that each point below is a point that lies on the
unit circle and the terminal arm of Ө
(i) Sketch a diagram
(ii) Determine all trig ratios
(iii) Determine the angle of rotation from standard position
(a) 119875 (5
13 minus
12
13) (b) 119875 (minus
1
2
radic3
2)
x
y
x
y
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 21
(IV) Exact Values of Trig Ratios
Exact values for the trigonometric ratios can be determined using
special triangles (30deg-60deg-90deg) or (45deg-45deg-90deg) and multiples of
120579 = 0120587
6
120587
4
120587
3
120587
2 or θ = 0deg 30deg 45deg 60deg 90deg for points P(θ) on
the unit circle
Special angles of rotation on the unit circle occur in terminal positions
where the reference angle is 30deg 45deg and 60deg
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 22
If we consider the first quadrant and the terminal positions for
30deg 45deg and 60deg we can develop the side lengths in the resulting
triangle
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 23
For the unit circle identify the EXACT COORDINATES of each point
indicated
Exact Values of Special Angles
(A) 30deg ndash 60deg ndash 90deg Triangles
(B) 45deg ndash 45deg ndash 90deg Triangles
Note the pattern
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 24
Example Determining an EXACT VALUE given a trig ratio
Include a sketch to determine the EXACT VALUE for each trig ratio
(a) sin (minus4120587
3) (b) sec (
7120587
6)
(c) cot 270deg
x
y
x
y
x
y
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 25
Example Determine the EXACT VALUE of each trig expression
(a) csc2 (120587
3) + cot2 (
11120587
4) (b)
cot(120587
3)+cos(
11120587
3)
csc(minus240deg)
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 26
(V) Approximate Values of Trig Ratios
Approximate values for sine cosine and tangent can be
determined for angles measured in degrees or radians The mode of
the calculator can be set to degrees or radians
cos 60deg = _____ (degree mode) sin (-30deg) = _____ (degree mode)
cos 60 = _____ (radian mode) sin (-30) = _____ (radian mode)
To evaluate cosecant secant or cotangent using the correct reciprocal
relationship For example to determine the value of sec 33 you would
use the ldquocosrdquo function on your calculator Thus
13 3 sec
Example Determine the approximate value (4 decimal places) for
(a) csc (7120587
5) (b) cot (23) (c) cot (210deg)
P201 ndash P202 1 2 8 9
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 27
43 Trigonometric Ratios (Part II)
Determining Where a Trig Ratio is Positive or Negative
The placement of a terminal arm in a quadrant will implicate that
some trig ratios will be positive and others negative
x
y
Goals
Determining Where a Trig Ratio is Positive or Negative
Determining Angles of a Trig Ratio over a Specified Domain
Given a Trig Ratio Determine other Trig Ratios
Given a Point on Terminal Arm Determine over a Specified Domain
Given Points on Terminal Arm Determine Arc Length
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 28
Example Identify the quadrant(s) where
(a) sin Ө gt 0 (b) tan Ө lt 0 (c) csc Ө lt 0
(d) sec Ө gt 0 and cot Ө lt 0
(VI) Determining angles given a trig ratio over a specified domain
Example Determine all of the angles within the specified domain
that satisfies the given trig ratio
(a) sec 120579 = minusradic2 where ndash2π le Ө le 2π
x
y
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 29
(b) csc 120579 = minus2 where ndash180deg le Ө lt 180deg
(c) tan Ө = ndash24567 where 0 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 30
(VII) Given a trig ratio determine other trig ratios
Example Determine the EXACT VALUE of the other five trig
ratios under the given conditions
(a) sin 120579 = minus1
2 where 180deg le Ө lt 270deg
(b) sec Ө = 55 where 3120587
2 le Ө le 2π
x
y
x
y
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 31
(VIII) Given a point on the terminal arm determine Ө in the
specified domain
Example P(ndash5 12) where ndash360deg le Ө lt 360deg
(IX) Given points on the terminal arm determine arc length
Example Determine the length of 119860 to the nearest
tenth of a unit
x
y
B (-86)A (-68)
Q
P201 ndash P202 3 ndash 7 10 ndash 12 18 19 21 C2
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 32
44 Introduction to Trigonometric Equations
Remember ndash Placement of a Terminal Arm based on a Trig Ratio
Example Where is
(a) csc Ө lt 0 (b) tan Ө gt 0
(I) Stating a Domain using Set Notation vs Interval Notation
When we use set notation to express a domain such as 0 le Ө le π
It can also be expressed using interval notation as
Therefore Ө є (0 π] is the same as _____________
Express ndashπ lt Ө le 2π using interval notation ____________
x
y
A
C
S
T
C ndash Cosine (amp Sec) are positive
A ndash All trig ratios are positive
S ndash Sine (amp Csc) are positive
T ndash Tangent (amp Cot) are positive
Goals
Stating a Domain Using Set Notation vs Interval Notation
Solving Linear Trig Equations
Solving Quadratic Trig Equations
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 33
(II) Solving Linear Trig Equations a + b = 0
So far we have solved trig ratios where we havenrsquot had to isolate
the trig ratio
Example Solve for Ө where csc Ө = ndash radic2 where Ө є [0 2π]
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 34
Sometimes we have to isolate the trig ratio to solve
Example Solve for all possible values of Ө where
radic3sec Ө + 2= 0
Example Solve for all possible values of Ө where
5sin Ө + 2 = 1 + 3sin Ө 0deg le Ө lt 360deg
x
y
x
y
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 35
(III) Solving Quadratic Trig Equations a + b +c=0
Example Solve the following trig equations for the specified
domain
(a) 2 sin2Ө = ndash 5 sin Ө + 3 Ө є (ndashπ 2π)
Sin2 Ө
cos2 Ө
tan2 Ө
csc2 Ө
sec2 Ө
cot2 Ө
sin Ө
cos Ө
tan Ө
csc Ө
sec Ө
cot Ө
x
y
x
y
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 36
(b) 5 sec2Ө = 12 + 4sec Ө for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 37
(c) 2 csc2Ө ndash 8 = 0 for all Ө in radians
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822
Unit 4 Math 3200 38
(d) Given g(Ө) = cos2Ө ndash 3 and p(Ө) = 2 cos Ө determine the
values of Ө such that g(Ө) = p(Ө) where Ө є [0 4π]
Give solutions as exact values where possible Otherwise
give approximate measures to the nearest thousandth of a
degree
x
y
x
y
Textbook Homework pg 211 1-5 9-11 16 17 1822