√75 sin(1140°)+4cos(780°}-ctg^2(30°)

Question

√75 sin(1140°)+4cos(780°}-ctg^2(30°)

Answer 1

5√3sin(1080+60)+4cos(720+60)-ctg²30=5√3sin60+4cos60-ctg²30=
=5√3*√3/2+4*1/2-(√3)²=7,5+2-3=6,5