Trigonometric Equations (Edexcel A-Level Mathematics): Flashcards

Equations involving trigonometric functions in linear form.

Move other terms to one side, leaving trig function alone.

$\theta = \sin^{-1}(k)$ or $\theta = 180° - \sin^{-1}(k) + 360°n$.

$\theta = \cos^{-1}(k) + 360°n$ or $\theta = -\cos^{-1}(k) + 360°n$.

$\theta = \tan^{-1}(k) + 180°n$ for all solutions.

Ensure solutions are in the specified interval given.

$\theta = 30°$ and $\theta = 150°$ within $0°$ to $360°$ interval.

$\theta = 120°$ and $\theta = 240°$ within $0°$ to $360°$ interval.

$\theta = \sin^{-1}(k) + 360°n$ or $180° - \sin^{-1}(k) + 360°n$.

Find angles using $\theta = \tan^{-1}(0.27)$ and adjust for multiples.