# How to prove #sin^2 theta - cos^2 theta = 1 -2cos^2 theta# ?

##### 1 Answer

Jul 17, 2018

See answer below

#### Explanation:

Given: Prove

Use the Pythagorean Identity:

Rearrange the identity:

Start with the left side of the equation and substitute the rearranged identity:

Combine like-terms:

Q.E.D.