f(x)=sin(π/4+x)sin(π/4-x)=sin(π/4+x)cos(π/4+x)=(1/2)sin2(π/4+x)=(1/2)sin(π/2+2x)周期为T=2π/2=π当x=0时,f(0)=(1/2)sin(π/2)=(1/2)是最大值,所以x=0是对称轴答B.周期为π的偶函数
