Trigonometry Examples

$\cos (2 x) = 1 - 2 \sin^{2} (x)$

Step 1

Start on the right side.

$1 - 2 \sin^{2} (x)$

Step 2

Apply the cosine double-angle identity.

$\cos (2 x)$

Step 3

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

$\cos (2 x) = 1 - 2 \sin^{2} (x)$ is an identity