f(x)=sin2x+cos2x=sin(2x+π/4)平移则f(x)=[2(x-φ)+π/4]x=0是对称轴则f(0)=±1所以2(0-φ)+π/4=kπ+π/2φ=-kπ/2-π/8所以k=-1最小是3π/8
