Practice!

Sample Problem

Use x=4sin θ to

a) write 4=as a trigonometric equation of θ, where –π/2<θ<π/2.

4=4sin θ

4=4cos θ

4=4(sin θ+cos θ)

4=√sin2θ-cos2θ

b) Find sin θ

0

-1

1

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3)Find cos θ.

0

1/4

1

-1/4

Solution

1) 4= ===4cosθ

1 = cos θ

Θ = 0

2) Sin θ = 0 ;

3) cos θ = 1