Inverse Trigonometric Identity Using a Right Triangle

Inverse Trigonometric Identity Using a Right Triangle

## Formula

If:

$$\theta=\tan^{-1}x$$

then:

$$\sin\theta=\frac{x}{\sqrt{1+x^2}}$$

and:

$$\cos\theta=\frac1{\sqrt{1+x^2}}$$

## Usage

- Used as the standard substitution technique for converting between inverse tangent and sine/cosine expressions.