4cos(3n/12-n/6)+ctg(n/6-n/12)
4cos(n/12)+ctg(n/12)
cos(n/12)(4+1/sin(n/12))
4 cos (3d-n/6)+ ctg (d+n/12)=4 cos (3п/6-n/6)+ ctg (п/6+n/12) =
4 cos (n/3)+ ctg (n/4)=4*0,5+1=3
