Find the exact values of the following trigonometric expressions without using a…

MATHEMATICS · Multi-part · A Level · Mathematics · Trigonometry · Trigonometry

Problem

Find the exact values of the following trigonometric expressions without using a calculator. Show every intermediate step clearly. (i)

\sin 675^{\circ}

(ii)

\cos (-420^{\circ})

(iii)

\tan 870^{\circ}