∵f（x）＝2sin（2x－π/6）＋2cos2x＝2sin2xcos（π/6）－2cos2xsin（π/6）＋2cos2x＝√3sin2x－cos2x＋2cos2x＝√3sin2x＋cos2x＝2［（√3/2）sin2x＋（1/2）cos2x］＝2［sin2xcos（π/6）＋cos2xsin（π/6）］＝...