Задание 3410

а) $x = -\frac{\pi}{3} + 2\pi k,\ x = \frac{\pi}{4} + 2\pi k,\ x = \frac{2\pi}{3} + 2\pi k,\ x = \frac{3\pi}{4} + 2\pi k,\ k \in \mathbb{Z}$;

б) $x = -\frac{\pi}{3},\ x = \frac{\pi}{4}$.