# How do you prove the identity #tan^4x+tan^2x+1=(1-cos^2x)(sin^2x)/(cos^4x)#?

##### 1 Answer

Sep 22, 2015

You don't, because it's false.

#### Explanation:

We know the Pythagorean identity that

So we know that

Since

Cancelling the

Or

Which doesn't have any solutions, therefore the equation is false for all values of x.