f(x)=sin(2x)+cos(2x)=(√2/2)cos(2x)+(√2/2)sin(2x)=cos(2x-π/4)设平移后得g(x)g(x)=cos[2(x-φ)-π/4]=cos(2x-2φ-π/4)令-2φ-π/4=-π2φ=3π/4φ=3π/8选C
