General Solutions of Trigonometric Equations

Lesson · Beginner

Trigonometry

sinα=sinβα=β+360k, 180β+360k,kZcosα=cosβα=±β+360k,kZtanα=tanβα=β+180k,kZcotα=cotβα=β+180k,kZ \begin{aligned} \sin\alpha=\sin\beta &\Rightarrow \alpha=\beta+360^\circ k,\ 180^\circ-\beta+360^\circ k, \quad k\in\mathbb Z \\[12pt] \cos\alpha=\cos\beta &\Rightarrow \alpha=\pm\beta+360^\circ k, \quad k\in\mathbb Z \\[12pt] \tan\alpha=\tan\beta &\Rightarrow \alpha=\beta+180^\circ k, \quad k\in\mathbb Z \\[12pt] \cot\alpha=\cot\beta &\Rightarrow \alpha=\beta+180^\circ k, \quad k\in\mathbb Z \end{aligned}