15.5 Double Angle Identities

Double Angle Identities

sin2 2sin cos

cos2 cos2 sin2cos2 2cos2 1cos2 1 2sin2

tan2 2 tan1 tan2

Find sin2x for the angle in the given quadrant satisfying the given condition.

1. 3; sin

5III x

Find sin2x for the angle in the given quadrant satisfying the given condition.

2. I; tan x 2 10

3

Find cos2x for the angle in the given quadrant satisfying the given condition.

3. II; sin x 2

5

Find cos2x for the angle in the given quadrant satisfying the given condition.

4. II; cos x 3

10

Find tan2x for the angle in the given quadrant satisfying the given condition.

5. andsin x 8

17 x

32

Find tan2x for the angle in the given quadrant satisfying the given condition.

6. andtan x 21

22

x

Use the given information to find sin2θ, cos2θ, and tan2θ .

7. andsin 1

30

2