Question

Решите тригонометрическое неравенство 2cos(x+П/3)<-1

Answer 1

$2cos(x+\frac{\pi}{3})\ \textless \ -1\\\\cos(x+\frac{\pi}{3})\ \textless \ -\frac{1}{2}\\\\\frac{2\pi}{3}+2\pi n\ \textless \ x+\frac{\pi}{3}\ \textless \ \frac{4\pi }{3}+2\pi n,\; n\in Z \\\\ \frac{\pi }{3} +2\pi n\ \textless \ x\ \textless \ \pi +2\pi n \; ,\; n\in Z\\\\x\in ( \frac{\pi }{3}+2\pi n\; ;\; \pi +2\pi n)$