Derive the identity

MATHEMATICS · Subjective · A Level · Mathematics · Trigonometry · Trigonometry

Problem

Derive the identity tan⁡3θ=3tan⁡θ−tan⁡3θ1−3tan⁡2θ\displaystyle \tan 3\theta = \dfrac{3\tan\theta - \tan^{3}\theta}{1 - 3\tan^{2}\theta}, where θ≠π2+nπ\theta \neq \frac{\pi}{2} + n\pi.

Related theory

Browse the problem library