Prove identity

Dearest Melody, it's juriemagic here...working from my phone....uhm, I made an error..it's supposed be \(1+sec^2x\)

Melody, no, I am really stuck...please help me...

I think it's supposed to be    sec^2 x - 1

To see why.....the left hand side  can be factored as

tan^2x  (sin^2 x + cos^2 x)  =

tan^2 x ( 1)  =

tan^2 x

But 

tan^2x =  sec^2 x - 1      add 1 to both sides

tan^2 x + 1  =  sec^2 x      which is an identity

Thank you CPhill, I do appreciate it all!