g(x)=sin2x+cos2x=√2sin(2x+π/4)其最小正周期t=2π/2=π而f(x)=|sin2x+cos2x│=│√2sin(2x+π/4)│表示将g(x)=√2sin(2x+π/4)图像中x轴下半部分沿x轴翻折，∴f(x)的最小正周期T=π/2
