Consider the radian measure

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

Problem

\dfrac{7\pi}{12}

. Answer the following. (i) Rewrite

\dfrac{7\pi}{12}

as a sum or difference of two standard angles expressed in radians. (ii) Using your decomposition from part (i), obtain the exact value of

\sin \dfrac{7\pi}{12}

. (iii) Hence, determine the exact value of

\cos \dfrac{7\pi}{12}