Verify this trigonometric equation help please!

Question

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

Answer 1

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

tanx=sinx/cosx

secx=1/cosx

=-(sinx/cosx)^2+(1/cosx)^2

=(-sin^2x+1)/cos^2x

Here -sin^2x+1=cos^2x

=cos^2x/cos^2x

=1