Question

Question #ed6c3

Answer 1

`LHS=sin^2xcos^2y - cos^2xsin^2y`

`=(1-cos^2x)cos^2y - cos^2x(1-cos^2y`

`=cos^2y-cancel(cos^2xcos^2y) - cos^2x+cancel(cos^2cos^2y)`

`=cos^2y - cos^2x=RHS`

Proved