Trigonometry Examples

$\cos (x + y) \cos (x - y) = \cos^{2} (x) - \sin^{2} (y)$

Step 1

The provided equation is an identity.

$\cos (x + y) \cos (x - y) = \cos^{2} (x) - \sin^{2} (y)$ is an identity

$[\begin{array}{c} x^{2} & \frac{1}{2} \\ \sqrt{π} & \int x d x \end{array}]$