Question

Найдите значение выражения:
а) 4 cos 240° - 3 tg 135°
b) sin 4П3 + cos 11П6

Answer 1

a) 4Cos240° - 3tg135° = 4Cos(180° + 60°) - 3tg (90° + 45°) = - 4Cos60° +
+ 3ctg45° = - 4 * 1/2 + 3 *1 = - 2 + 3 = 1
б) Sin 4π/3 + Cos 11π/6 = Sin(π + π/3) + Cos(2π - π/6) = - Sin π/3 + Cosπ/6=
= - √3/2 + √3/2 = 0