Question

How do you use the fundamental identities to simplify `cos^2y/(1-siny)`?

Answer 1

The pythagorean identity `sin^2x + cos^2x = 1` can be solved for `cos^2x`.

`=(1 - sin^2y)/(1 - siny)`

`=((1 + siny)(1 - siny))/(1 - siny)`

`=1 + siny`

Hopefully this helps!