y=4cos??x+4√3 sinx cosx-2 =2(1+cos2x)+2√3 sin2x-2 =4(√3 /2sin2x+1/2cos2x) =4sin(2x+π/6) 1.T=2π/2=π 2.最大值为4 ,此时2x+π/6=π/2+2kπ,k∈Z即x=kπ+π/63.2kπ-π/2<2x+π/6<2kπ+π/2即[kπ-π/3,kπ+π/6]4.2x+π/6=π/2+kπ,k∈Z,x=1/2kπ+π/6