### 3 Answers

Relevance

- Anonymous4 weeks ago
Do you mean what it is simplified? Then cos^2x-1 = cos^2x-1^2 = (cosx+1)*(cosx-1)

Or do you mean using the trigonometrical one? Then cos^2x-1 = cos^2x-(sin^2x+cos^2x) = cos^2x - cos^2x - sin^2x = -sin^2x

Still have questions? Get your answers by asking now.