y=sin²(x+π/4)+sin(x+π/4)sin(x-π/4)=sin(x+π/4)(sin(x+π/4)+sin(x-π/4))=sin(x+π/4)(2sin(x)cos(π/4))=(√2)sin(x+π/4)sin(x)=(-√2/2)[cos(2x+π/4)-cos(π/4)]=(-√2/2)cos(2x+π/4)+1/2=(-√2/2)c...