Trigonometric identities (AQA GCSE Further Maths): Flashcards

Equations involving trig functions that are true for all values

$\equiv$ (equivalence symbol)

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

$\sin^2\theta = 1 - \cos^2\theta$

$\cos^2\theta = 1 - \sin^2\theta$

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

Express everything in terms of a single trig function

Work with one side at a time

$\frac{1}{2}$

$\frac{\sqrt{3}}{2}$

$\frac{1}{\sqrt{2}}$

$1$

$\frac{\sqrt{3}}{2}$

$\frac{1}{2}$

$|\sin x|$ (not necessarily $\sin x$)