need help understanding this pre calc question

Question

Answer 1

cot²x/(cscx + 1) = (1 - sinx)/sinx; We have to prove this identity.

cot²x/(cscx + 1) = (csc²x - 1)/(1 + cscx) = (1 - cscx)(1 + cscx)/(1 + cscx) = 1 - cscx = 1 - 1/sinx = (sinx - 1)/sinx