Вопрос:

9. Найдите \(\sin 150^\circ\), \(\cos 150^\circ\), \(\operatorname{tg}150^\circ\), \(\operatorname{ctg}150^\circ\).

Ответ:

Угол \(150^\circ=180^\circ-30^\circ\), поэтому:

\(\sin 150^\circ=\sin 30^\circ=\frac{1}{2}\);

\(\cos 150^\circ=-\cos 30^\circ=-\frac{\sqrt{3}}{2}\);

\(\operatorname{tg}150^\circ=-\operatorname{tg}30^\circ=-\frac{\sqrt{3}}{3}\);

\(\operatorname{ctg}150^\circ=-\operatorname{ctg}30^\circ=-\sqrt{3}\).

Ответ: \(\sin 150^\circ=\frac12\), \(\cos 150^\circ=-\frac{\sqrt3}{2}\), \(\operatorname{tg}150^\circ=-\frac{\sqrt3}{3}\), \(\operatorname{ctg}150^\circ=-\sqrt3\).