Question

2 cos(x + п/3)= ≥ √2

Answer 1

Ответ:

$2 \cos(x + \frac{\pi}{3} ) \geqslant \sqrt{2} \\ \cos(x + \frac{\pi}{3} ) \geqslant \frac{ \sqrt{2} }{2}$

рисунок

$x + \frac{\pi}{3} ∈[- \frac{\pi}{4} + 2\pi \: n ;\frac{\pi}{4} + 2 \pi \: n] \\ x∈[- \frac{7\pi}{12} + 2\pi \: n ;- \frac{\pi}{12} + 2\pi \: n]$