How to solve sinx cosx tanx= 1- cos^2x ?

1 Answer
Nov 19, 2017

Please see below.

Explanation:

We know that tanx=sinx/cosx

Let's plug it in:

sinxcosx*sinx/cosx=1-cos^2x

sinxcancelcosx*sinx/cancelcosx=1-cos^2x

sin^2x=1-cos^2x

But we know the most famous Trigonometric identity says:

sin^2x+cos^2x=1

If we subtract cos^2x from both sides, we get:

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

sin^2x=1-cos^2x

We can plug it in:

1-cos^2x=1-cos^2x

You now have the proof.