Question

How do you prove `sin^2 theta-cos^2 theta=2sin^2 theta-1`?

Answer 1

Use the pythagorean identity `sin^2theta + cos^2theta = 1`.

Explanation:

Manipulating the identity, we get: `sin^2theta - 1 = -cos^2theta`

`sin^2theta + sin^2theta - 1 =`

`2sin^2theta - 1 = ->` Identity proved

Hopefully this helps!