1. Вычислите: a) $$\sin 300^{\circ}$$; б) $$\operatorname{tg}(-\frac{2\pi}{3})$$; в) $$2\sin \frac{\pi}{3} - \cos \frac{\pi}{2}$$

a) $$\sin 300^{\circ} = \sin (360^{\circ} - 60^{\circ}) = -\sin 60^{\circ} = -\frac{\sqrt{3}}{2}$$. б) $$\operatorname{tg}(-\frac{2\pi}{3}) = -\operatorname{tg}(\frac{2\pi}{3}) = -\operatorname{tg}(\pi - \frac{\pi}{3}) = \operatorname{tg}(\frac{\pi}{3}) = \sqrt{3}$$. в) $$2\sin \frac{\pi}{3} - \cos \frac{\pi}{2} = 2 \cdot \frac{\sqrt{3}}{2} - 0 = \sqrt{3}$$. Ответ: a) $$-\frac{\sqrt{3}}{2}$$; б) $$\sqrt{3}$$; в) $$\sqrt{3}$$