4.4 4 cos(-600°) - tg(-870°) sin 1200°

cos(-600°) = cos(-600°+2*360°) = cos(120°) = -1/2; tg(-870°) = tg(-870° + 3*360°) = tg(210°) = tg(180°+30°) = tg(30°) = 1/√3; sin(1200°) = sin(1200°-3*360°) = sin(120°) = sin(180°-60°) = sin(60°) = √3/2. 4*(-1/2) - (1/√3) * (√3/2) = -2 -1/2 = -2.5