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Signs of functions in each quadrant
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900 :1Quadrant
I
18009 :2Quadrant
II
270018 :3Quadrant
III
360027 :4Quadrant
IV
56 :1Quadrant
To determine sign (pos or neg), just pick angle in quadrant and determine sign.
positive 906.65sin
positive 422.65cos
001 :2Quadrant positive 984.100sin
negative 173.100cos
Now do Quadrants III and IV.
cos
sin
cos
sin
cos
sin
cos
sin
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IIIquadrant in lies 250 a.
IIIquadrant
negative issin because negative, b.
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positive means 0sin negative means 0cos
In what quadrant is sin positive and cos negative?
cos
sin
cos
sin
cos
sin
cos
sin
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cos
sin
cos
sin
cos
sin
cos
sin
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positiveboth
positive cos means 0cos A
negative issin cos means 0sincos AA __
sin and cos is Where
positive.sin means 2
2xsin
negative. cos means 2
2xcos
sin and cos is Where
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The UNIT CIRCLE sin determine
circle,unit theUsing
hyp
oppsin
1
b b
os determine
circle,unit theUsing
c
hyp
adjcos
1
a a
.equivalent with their
b & a replacecan weNowcos
sin
sin,cos, PbaP
sin,cosP
Any point on the unit circle can be found by taking the cos and sin of the given angle.
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cos
sin
3524,.425.P
cos 2.
sin 1.
:following thedetermine circle,unit the
on 3524,.425.point Given P
Every point on the unit circle has coordinates
sin,cosP
So, when they ask you to determine the sin of theta, it is just the second coordinate.
3524.sin
425.cos
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3.5sin .5cos
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3
5sin
3
2cos
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cos
sin
REMEMBER
ABsin
OBcos
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2
1cos
2
2sin
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cos
sin
cos
sin
cos
sin
cos
sin
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cos
sin
cos
sin
cos
sin
cos
sin
