y=1/2cos^x+√3/2sinxcosx+1 =(1+cos2x)/4+√3/4sin2x+1 =(√3/4sin2x+1/4cos2x)+5/4 =1/2sin(2x+π/6)+5/4取最大值则时,满足sin(2x+π/6)=1即2x+π/6=2kπ+π/2 2x=2kπ+π/3 x=kπ+π/6X={x|x=kπ+π/6 k∈Z}
cos²x=(cosx)²知道吗？
