a) sin 300°
$$sin(300°) = sin(360° - 60°) = -sin(60°) = -\frac{\sqrt{3}}{2}$$
Ответ: $$-\frac{\sqrt{3}}{2}$$
б) tg (-$$\frac{2π}{3}$$)
$$tg(-\frac{2π}{3}) = -tg(\frac{2π}{3}) = -tg(π - \frac{π}{3}) = -(-tg(\frac{π}{3})) = tg(\frac{π}{3}) = \sqrt{3}$$
Ответ: $$\sqrt{3}$$
в) 2sin$$\frac{π}{3}$$-cos$$\frac{π}{2}$$
$$2sin(\frac{π}{3}) - cos(\frac{π}{2}) = 2 * \frac{\sqrt{3}}{2} - 0 = \sqrt{3}$$
Ответ: $$\sqrt{3}$$