Question

How do you verify the identity: `sec x - cos x = sin x tan x`?

Answer 1

It can be prooven by transforming right side of the equality to the left.

`R = sinx*tanx=sinx*sinx/cosx=sin^2x/cosx=(1-cos^2x)/cosx=1/cosx-cosx=secx-cosx=L`

QED