原式=cosα+(-1/2)cosα+(√3/2)sinα+(-1/2)cosa-(√3/2)sinα =0祝你开心!希望能帮到你,如果不懂,请追问,祝学习进步!O(∩_∩)O
cosα+cos(2π/3-α)+cos(2π/3+α)=cosα+cos(2π/3)cosα+sin(2π/3)sinα+cos(2π/3)cosα-sin(2π/3)sinα=cosα+2cos(2π/3)cosα=cosα-cosα=0