# Thread: Find sin(alpha + beta) and cos(alpha + beta) and Quadrant of the angle (alpha + beta)

1. ## Find sin(alpha + beta) and cos(alpha + beta) and Quadrant of the angle (alpha + beta)

Given sin alpha = 2/5 , cos beta = -1/3 alpha is in quadrant 2 and beta is in quadrant 3.

Find sin(alpha + beta) and cos(alpha + beta) and Quadrant of the angle (alpha + beta). Circle your final answers or underline your final answrs and exact answers only.

2. ## Re: Find sin(alpha + beta) and cos(alpha + beta) and Quadrant of the angle (alpha + b

Surely you have been given the angle-sum identities for sine and cosine. Use them. To get the other values you need, use the Pythagorean Identity.