Trigonometry Examples

$\tan (2 x) = \frac{2 \tan (x)}{1 - \tan^{2} (x)}$

Step 1

Start on the left side.

$\tan (2 x)$

Step 2

Apply the tangent double-angle identity.

$\frac{2 \tan (x)}{1 - \tan^{2} (x)}$

Step 3

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

$\tan (2 x) = \frac{2 \tan (x)}{1 - \tan^{2} (x)}$ is an identity