y=sin2x+√3*cos2x =2(1/2*sin2x+√3/2*cos2x) =2sin(2x+π/3) 函数的周期为：T=2kπ/2=kπ,k为整数 ∵-1≤sin(2x+π/3)≤1 ∴函数的值域为：[-2,2]
