Question

tg2xменьше или равно минус 1

Answer 1

$tg2x \leq -1\\-\frac{\pi}{2} +\pi k<2x\leq -\frac{\pi}{4} +\pi k\\-\frac{\pi}{4} +\frac{\pi k}{2}<x\leq -\frac{\pi}{8} +\frac{\pi k}{2}$