Question

How do you prove `cosx - sinx - cos^3x/cosx = sin^2x - tanx`?

Answer 1

Prove trig identity

Explanation:

`cos x - sin x - (cos^3 x)/cos x = (cos^2 x - cos^3 x - sin x)/cos x =`

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

`= sin^2 x - tan x`