# What are the exact values of cos 150° and sin 150°?

Jan 9, 2017

$\cos 150 = - \frac{\sqrt{3}}{2}$
$\sin 150 = \frac{1}{2}$
$\cos 150 = \cos \left(- 30 + 180\right) = - \cos \left(- 30\right) =$
$- \cos 30 = - \frac{\sqrt{3}}{2}$
$\sin 150 = \sin \left(- 30 + 180\right) = \sin 30 = \frac{1}{2}$