y=sinx(sinxcos60+cosxsin60)=1/2(sinx)^2+√3/2*sinxcosxcos2x=1-2(sinx)^2,所以(sinx)^2=(1-cos2x)/2sin2x=2sinxcosx,sinxcosx=1/2*sin2x所以y=√3/4*sin2x-1/4*cos2x+1/4=√[(√3/4)^2+(1/4)^2]*sin(2x-a)+1/4=1/...