Question

Question #1bd72

Answer 1

See proof below

Explanation:

We need

`secx=1/cosx`

`1+tan^2x=sec^2x`

`RHS=(1+2sinxcosx)/cos^2x`

`=1/cos^2x+(2sinxcosx)/cos^2x`

`=sec^2x+(2sinx)/cosx`

`=1+tan^2x+2tanx`

`=(1+tanx)^2`

`=LHS`

`QED`