1.解: (1)原式=cos(2x-π/3)-2sin(x–π/4)cos(x–π/4) =cos(2x-π/3)-sin(2x-π/2) =cos 2x cos π/3 + sin 2x sin π/3 - sin 2x cos π/2 + sin π/2 cos 2x =3/2cos 2x + 根号3/2 sin 2x =2倍根号3/2sin(2x+π/6) 所以 最小正周期W=2π/2=π 对称轴方程为π/4+kπ (2)当x=-π/12时 上式为0 当x=π/2时 上式为-根号3/2 所以值域为[-根号3/2,0]