1) Решим уравнение sin2x = -1/2
$$2x = arcsin(-1/2) + 2\pi n, n \in Z$$
$$2x = -\frac{\pi}{6} + 2\pi n, n \in Z$$ или $$2x = \pi - (-\frac{\pi}{6}) + 2\pi n, n \in Z$$
$$2x = -\frac{\pi}{6} + 2\pi n, n \in Z$$ или $$2x = \frac{7\pi}{6} + 2\pi n, n \in Z$$
$$x = -\frac{\pi}{12} + \pi n, n \in Z$$ или $$x = \frac{7\pi}{12} + \pi n, n \in Z$$
Ответ: $$x = -\frac{\pi}{12} + \pi n, n \in Z$$ или $$x = \frac{7\pi}{12} + \pi n, n \in Z$$