解法一：f(x)=sin(2X+π/4)+cos(2X+π/4)=√2[√2/2sin(2X+π/4)+√2/2cos(2X+π/4)]=√2sin(2x+π/4+π/4)=√2sin(2x+π/2)=√2cos2x.解法二：f(x)=sin(2X+π/4)+cos(2X+π/4)=√2/2sin2x+√2/2cos2x+√2/2cos2x-√...