f（x）＝2sin（wx－π/3）coswx＋2cos（2wx＋π/6）
=2(sinwxcosπ/3-coswxsinπ/3)coswx+2cos(2wx+π/6)
=sinwxcoswx-√3(coswx)^2+2cos(2wx+π/6)√3cos2wx-sin2wx
=1/2sin2wx-√3/2(1+cos2wx)+2cos(2wx+π/6)√3cos2wx-sin2wx
=-（√3/2cos2wx-1/2sin2wx）-√3/2+2cos(2wx+π/6)
=-cos(2wx+π/6)-√3/2+2cos(2wx+π/6)
=cos(2wx+π/6)-√3/2