A+ Answers

1.Rewrite the following expression as a simplified expression containing one term. 

2.Identify a and ß in the following expression, which is the right-hand side of the formula for cos (a –

ß).

cos (170°) cos (50°) + sin (170°) sin (50°) 

A. a = - 170°, ß = 50°

B. a = 170, ß = 50°

C.a = - 50°, ß = 170°

D.a = 50°, ß = - 170°

3.Use trigonometric identities to find the exact value of the expression below.  

4.Complete the identity given below. 

(sin x - cos x)

A.1 - sin 2x

B.1 - cos 2x

C.1 + cos 2x

D.sin 2x

5. Use a calculator to solve the following equation on the interval  Round the answer to two decimal places.

sin x = -0.29

A.3.44, 5.99

B.0.29, 3.44

C.0.29, 5.99

D.0.29, 1.87

6.Use a half-angle formula to find the exact value of the expression sin 165°.

7.To which of the expressions below is equivalent?

8.Express the product of sin 5x cos 2x as a sum or difference.

9.Use a half-angle formula to find the exact value of the expression cos 112.5°.

10.Solve the problem sin 8x – sin 2x.

A.2 sin 5x cos 3x

B.2 sin 3x

C.2 sin 3x cos 5x

D.2 cos 2x cos 5x

11.Find the exact value of the following by using a sum or difference identity. 

sin (185° - 65°)

12.Complete the following identity: 

A.sin

B.cot

C.1

D.cot

13. Which expression could be used to fill in the blank in sin x _______ = tan x to create a valid trigonometric identity?

A.cos x

B.sec x

C.tan x

D.sin x

14. Write 2 sin x cos 6x as a sum or difference of trigonometric functions.

A.cos 5x - cos 7x

B.sin 7x - sin 5x

C.sin 7x + sin 5x

D.cos 5x + cos 7x

15.Find the exact value of the expression cos (245° - 5°).

16.Using a double-angle formula, find cos 420°.

17.Which expression could you use to help you evaluate .

18.Solve the following equation on the interval  

19.Use the figure to find the exact value of the trigonometric function cos 2θ.  

20.Use trigonometric identities to find the exact value of the following expression.