Question

Нужно решить уравнение: ctg(pi/5-x)+1=0

Answer 1

$ctg(\frac{\pi}{5}-x)+1=0\\ctg(x-\frac{\pi}{5})=1\\x-\frac{\pi}{5}=\frac{\pi}{4}+\pi n\\x=\frac{\pi}{4}+\frac{\pi}{5}+\pi n\\x=\frac{9\pi}{20}+\pi n, \; n\in Z.$