Math — Trigonometric Identities

\sin^2\theta + \cos^2\theta = 1

\sin(A \pm B) = \sin A\cos B \pm \cos A\sin B

\cos(A \pm B) = \cos A\cos B \mp \sin A\sin B

\tan 2\theta = \frac{2\tan\theta}{1 - \tan^2\theta}