Question

(1+tan^2x)sin^2x=tan^2x

Answer 1

http://www.wolframalpha.com/input/?i=(1%2btan%5e2x)sin%5e2x%3dtan%5e2x&incTime=true

Answer 2

\(\large\color{black}{ \displaystyle (1+\tan^2x)\sin^2x=\tan^2x }\)

\(\large\color{black}{ \displaystyle (\sec^2x)\sin^2x=\tan^2x }\)

\(\large\color{black}{ \displaystyle \frac{1}{\cos^2x}\sin^2x=\frac{\sin^2x}{\cos^2x} }\)

Answer 3

and then you see it from there