Question

Sin Alpha = -7/25 and Cot Beta = -8/15. Neither Alpha nor Beta is in Quadrant 4. Find cos (alpha +Beta)

Answer 1

I think the cosine of a sum of two angles will be needed.

Answer 2

Right, you can find Sin Beta with (-7/25)^2 + Cos^2(alpha) =1

Answer 3

But my question is how do you convert Cot Beta into Sin and Cos

Answer 4

Yes, you can.

Answer 5

-8/15 = Cos/Sin..?

Answer 6

you can make a right triangle
\[\cot(\beta)=\frac{a}{o} \]