Precalculus Examples

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

Step 1

The provided equation is an identity.

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