f(x)=(1+cos2x)*(sinx)^2
=(1+cos2x)*[(1-cos2x)/2]
=[1-(cos2x)^2]/2
=(sin2x)^2/2
=[1-(cos4x)/2]/2
=-(1/4)cos4x+(1/2)
周期：T=2π/4=π/2
但不是偶函数,因为f(-x)≠f(x)