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