f(x)=cos(π/2-2x)+2sin(x-π/4)cos(π/2-(x+π/4))=sin2x+2sin(x-π/4)cos(π/4-x)=sin2x+2sin(x-π/4)cos(x-π/4)=sin2x+sin(2x-π/2)=sin2x-sin(π/2-2x)=sin2x-cos2x=根号2*sin(2x-π/4)故对称轴为x=3π/8+kπ/2...