sinx+cosx=√2(sinxcosπ/4+cosxsinπ/4)=√2sin(x+π/4)y = sinx+cosx+2sinxcosx= sinx+cosx+2sinxcosxsin^2x+cos^2x-1= sin^2x+2sinxcosx+cos^2x + sinx+cosx - 1= (sinx+cosx)^2+(sinx+cosx)-1= [√2sin(x+π/4)]...