Question

Вычислить cos(-4п/3) tg(-7п/6) ctg 5п/4

Answer 1

$Cos(- \frac{4 \pi }{3})=Cos ( \pi + \frac{ \pi }{3})= -Cos \frac{ \pi }{3} =- \frac{1}{2}$
$tg(- \frac{7 \pi }{6})=-tg( \pi + \frac{ \pi }{6})=-tg \frac{ \pi }{6}=- \frac{ \sqrt{3} }{3}$
$Ctg \frac{5 \pi }{4}=Ctg( \pi + \frac{ \pi }{4})=Ctg \frac{ \pi }{4}=1$