1. How do you prove sec2thetasin2theta = sec2theta - 1

2. how do you prove secant squared theta sine squared theta = cosecant squared theta - 1?

1. \sec2\theta\sin2\theta \equiv \sec2\theta - 1

This is not a valid identity.

2. \sec^2\theta \sin^2 \theta = \csc^2\theta - 1

Not valid either.