y=(√3)sin2x+cos2x
=2（√3/2sin2x+1/2cos2x)
=2(sin2xcosπ/6+cos2xsinπ/6)
=2sin(2x+π/6)
函数的最大值为2,最小值为-2
f(x)最小正周期T=2π/2=π