Trigonometric Identities and Equations (HSC SSCE Mathematics Advanced): Flashcards

True for all values of variable (except where undefined)

$\sec \theta = \frac{1}{\cos \theta}$

$\text{cosec } \theta = \frac{1}{\sin \theta}$

$\cot \theta = \frac{1}{\tan \theta}$

$\tan \theta = \frac{\sin \theta}{\cos \theta}$

$\cot \theta = \frac{\cos \theta}{\sin \theta}$

When $\cos \theta = 0$ (at $\theta = 90° + 180°n$)

When $\sin \theta = 0$ (at $\theta = 180°n$)

When their denominator equals zero

Work with one side, transform step-by-step to match the other