Prove each of the following identities.

a)tan^2x = 1 – cos^2x/cos^2x
b)sinx/1 – sin^2x = tanx/cosx

a)

RS = sin^2x/cos^2x
= LS

b) LS = sinx/cos^2x
= (sinx/cosx)/cosx
= tanx/cosx
= RS