1. Вычислите: a) sin 300°; б) tg(-2π/3); в) 2sin(π/3) - cos(π/2).

a) \( \sin 300^\circ = \sin (-60^\circ) = -\sin 60^\circ = -\frac{\sqrt{3}}{2} \); б) \( \tan(-\frac{2\pi}{3}) = \tan(-120^\circ) = \tan(-60^\circ) = -\frac{\sqrt{3}}{3} \); в) \( 2\sin \frac{\pi}{3} - \cos \frac{\pi}{2} = 2\cdot\frac{\sqrt{3}}{2} - 0 = \sqrt{3} \).