6-9

6.
Use an identity to find the exact value of the expression:
Note: You are not allowed to use decimals in your answer.

cos(π/8)) =

7.
Use an identity to find the exact value of the expression:
Note: You are not allowed to use decimals in your answer.

cos(247.5 degrees)) =

8.
Use an identity to find the exact value of the expression:
Note: You are not allowed to use decimals in your answer.

sin(π/8)) =

9.

Use an identity to find the exact value of the expression:
Note: You are not allowed to use decimals in your answer.

tan(π/8)) =