Question

cosx+cos(п/2-x)+cos(п+x)=0

Answer 1

Ответ:

$\cos(x) + \cos( \frac{\pi}{2} - x) \cos(\pi + x) = 0 \\ \cos(x) + \sin(x) - \cos(x) = 0 \\ \sin(x) = 0 \\ x = \pi \: n \\ n\in \: Z$