Question

Вычислите cos(-30°) sin660° ctg(-510)°

Answer 1

$cos(-30)=cos30= \frac{ \sqrt{3} }{2}\\\\sin660=sin(90*7+30)=-cos30=- \frac{ \sqrt{3} }{2}\\\\ctg(-510)=-ctg510=ctg(90*6-30)=-tg30=- \sqrt{3}$

Answer 2

=- Cos30°Sin(720° - 60°)Ctg(540° -30°)=
= - Cos30°Sin60°Ctg30° = -√3/2·√3/2·√3= -3√3/4