Find cos (u + v) .

Question

Given sin u = 8 17 , with u in quadrant I, and cos v = 21 29 , with v in quadrant I.

Answer 1

By The theorem of Pythagoras cos u = 15/17 and sin v = 20/29.

The cos(u+v) = cos u cos v - sin u sin v.

You do the arithmetic.