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Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 1
Trigonometric RatiosPrimary Trigonometric Ratios
Reciprocal Trigonometric Ratios
Primary Trig Ratios
sine
cosine
tangent
Reciprocal Trig Ratios
Points on the Unit Circle
sin
cos
tan
csc
sec
cot
Lesson 4.3 Trigonometric Ratios
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 2
Review:
or
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 3
Example:
The point lies at the intersection of the unit circle and the terminal arm of an angle is in standard position.
1) Draw a diagram to model the situation.
2) Determine the value of the six trigonometric ratios for in lowest terms.
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 4
Your Turn
The point lies at the intersection of the unit circle and the terminal arm of an angle is in standard position.
1) Draw a diagram to model the situation.
2) Determine the value of the six trigonometric ratios for in lowest terms.
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 5
Exact Values for Trigonometric Ratios
Exact values for the trigonometric ratios can be determined using:
i) the special triangles ( and
ii) multiples of for points unit circle
Example:
Determine the exact value for .
Method 1: Use Unit Circle
Method 2: Use Reference Angle
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 6
Example:
Determine the exact value for .
Example:
Determine the exact value for .
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 7
Example:
Determine the exact value for .
Example: Determine the exact values for each of the following:
(a)
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 8
(b)
(c)
(d)
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 9
Your Turn
(a)
(b)
(c)
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 10
(d)
(e)
P.202 #9
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 11
Approximate Values for Trigonometric Ratios
approximate values for sine, cosine and tangent using a calculator. The values of csc, sec and cot can be determined using the reciprocal relationship.
Example:
Determine the approximate value for
Example:
Determine the approximate value for
Example:
Determine the approximate value for
radian mode
degree mode
calculator must be in the appropriate mode: degree or radians
P.201 #2
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 12
Determine the Angle Measure given the Trigonometric Ratio
Review Math 2200Determine the value of where if .
Think About:
(1) What is the reference angle?
(2) In which quadrant does the angle terminate?
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 13
Example:
Determine the measure of all angles that satisfy the following conditions:
(i) where
(ii) where
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 14
(iii) where
(iv) where
P202 #10, 11
Lesson 4.3 Trigonometric Ratios
Trigonometry and Unit Circle 15
Calculate Trigonometric Values for Points not on the Unit Circle
Example:
The position A(4,3) lies on the terminal arm of an angle in standard position. What is the exact value of each trigonometric ratio for ?
P.202 #12