precalc homework 9

1. Evaluate the following:

a. cos75o− cos15o

b. sin − sin

2. Solve the following equations and write the general form of the solutions.

a. sin4θ + cos2θ = 0 Hint: Use the double angle identity for sin.

b. cos6θ− cos4θ = 0

3. Verify the following identity: = − cot(6θ)

4. Simplify the following:

a. cos65o− sin 25o

b. sin215o + sin2 75o

c. csc(−θ)

5. Solve the following right triangle. Round lengths to two decimal places and round angles to one tenth of a degree - Calculator required:

8

A

B

5

a

a. A =

b. B =

c. a =

6. From a spot 25 feet from the base of a building, the angle of elevation to the top of the building is 60o. Find the height of the building.