Question

Помогите не помню как делать ctg11П/3 Даю 20 балов

Answer 1

$ctg\frac{11\pi}{3}=ctg\frac{9\pi +2\pi }{3}=ctg(\frac{9\pi}{3}+\frac{2\pi}{3})=ctg(3\pi +\frac{2\pi}{3})=\\\\=ctg\frac{2\pi}{3}=ctg(\pi-\frac{\pi}{3})=-ctg\frac{\pi}{3}=-\frac{\sqrt3}{3}$