Question

The addition formula for cosine is shown below.

Answer 1

Explanation:

Sin(A) = 8/10

Cos(A) = 6/10

Sin(B) = 15/17

Cos(B) = 8/17

Cos(A+B) = 6/10 * 15/17 - 8/10 * 8/17

Cos(A +B) = 90/170 - 64/170

Cos(A + B) = 26/170