Задание 3411

а) $x = 2\pi k,\ x = \frac{\pi}{6} + 2\pi k,\ x = \frac{5\pi}{6} + 2\pi k,\ x = \pi + 2\pi k,\ k \in \mathbb{Z}$;

б) $x = -3\pi,\ x = -2\pi,\ x = -\frac{11\pi}{6}$.