Question

tg150-cos780+sin330
прошу помогите

Answer 1

$tg150-cos780+sin330=tg(180-30)-cos(360 \cdot 2+60)+$
$\displaystyle +sin(360-30)=-tg30-cos60-sin30= - \frac{ \sqrt 3}{3}- \frac{1}{2}- \frac{1}{2}=$
$\displaystyle = - \frac{ \sqrt 3}{3}- \frac{3}{3}= \frac{-(\sqrt 3+3)}{3}$