3) (Cos(-t)) / ctgt + Sin (5П+t) = Cost / (Cost/Sint) + Sin(П + t) =
= Sint - Sint = 0
5) √75Sin1140° + 4Cos(780°) - ctg²(30°) = √(25*3)Sin(360*3+60) +
+ 4Cos(360*2+ 60) - (√3)² = 5√3 * Sin60° + 4Cos60° - 3= 5√3 * √3/2 +4*1/2 - - 3 = 15/2 + 2 - 3 = 7,5 - 1 = 6,5