It ain't so. Note that for x =0, you get


\cos(0) \sin(0) \tan0 = \sec(0) \\
1 \times 0 \times 0 = 1\\
0 = 1


So the identity is incorrect.

verify cosx + sinx tanx=secx

verify cosx + sinx tanx=secx

In the furture please do not tag a new question onto an old post. Start a new thread instead.

This identity can be proved by replacing the tan(x) function with sin(x)/cos(x) and then combining the left hand side into a single fraction. Finally recall that cos^2x + sin^2x = 1.