Question

please help :

(1). If Cos α = -3/5 and sin β = 12/13 and α is in the second Quadrant β is also in the second Quadrant, find Sin(α + β), Sin(α - β), Cos(α + β), Cos(α - β), and determine in which quadrants α + β and α - β lie.

(2). If Cos α = 3/5 and sin β = - 9/41 and α is in the first Quadrant , β is in fourth Quadrant, find Sin(α + β), Sin(α - β), Cos(α + β), Cos(α - β), and determine in which quadrants α + β and α - β lie.

Answer 1

draw some triangles



then you can do the trig expansions and substitute the exact values.

Answer 2

you got this or no?