Inot to sure how to rewrite this problem sin^2 (y)/1-cos(y). can you explain how to rewrite.

Using trigonometric identities, sin^2(y) = 1 - cos^2(y).
If you substitute that in, you get 1- cos^2(y)/(1-cos(y)).
You can factorise 1 - cos^2(y) to be (1-cos(y))(1+cos(y)).
This means that the answer is 1 + cos(y) as the 1 - cos(y) will cancel. 

Ineed with this same question!