4 cos840 — корень из 48*sin600+ctg2^30.

4cos (360+480) -sqrt (48sin (360+240)+ctg2^30? cos (480) sin (240) ctg (360-α)=- ctg (α) ctg (270+α)=- tg (α) cos (120) -sin (120) ctg (360+α)=ctg (α) ctg (180-α)=- ctg (α) -cos (60) -sin (60) ctg (270-α)=tg (α) ctg (180+α)=ctg (α) ctg (90-α)=tg (α) ctg (90-α)=- tg (α)