Cot^2b (1-cos^2b)

Question

Can someone explain to me the procedure that I need to do with the trigonometric functions in order to get the answer

Answer 1

Look up the relationship between the cotangent^2 b, sine^2 b, and cosine^2 b. Substitute the equivalent sine and cosine functions in place of the cotangent. Rearrange sin^2 b + cos^2 b =1 and substitute for 1 - cos^2 b.

Cancel terms where appropriate.

Answer I got: cos^2 b