Trigonometry Examples

$\sin (2 x) = 2 \sin (x) \cdot \cos (x)$

Start on the right side.

$2 \sin (x) \cdot \cos (x)$

Apply the sine double-angle identity.

$\sin (2 x)$

Because the two sides have been shown to be equivalent, the equation is an identity.

$\sin (2 x) = 2 \sin (x) \cdot \cos (x)$ is an identity