Question

If α and β are the measures of two first quadrant angles and sin α =4/5 and sin β=5/13, find sin (α+β)

Answer 1

Are you familiar with the trig addition identities?

This is the one you need.

\(\sin (\alpha + \beta) = \sin \alpha \cos \beta + \sin \beta \cos \alpha \)

First, you need to find the cosines of those two angles.

Answer 2

Okay

Answer 3

cos α is 3/5 right?

Answer 4

and cos β is 12/13