1. sin (x) (cos^2 (x)) - sin (x)

My answer: -sin^3 (x)

2. sin (x) + cot (x) (cos (x))

My answer: csc (x)

3. (sec^2 (x) - 1) / sec^2 (x)

I only go to the part where its

(tan^2 (x)) / 1 + tan^2 (x)

i dont know what to do now..

Thank you once again