sin(2x+π/3）-√3sin(2x+5π/6﹚
＝sin(2x+π/3）＋√3sin﹙2x－π／6﹚
＝sin(2x+π/3）-√3cos﹙2x+π/3﹚
＝2[½sin(2x+π/3）－√3／2cos﹙2x+π/3﹚]
＝2sin2x