作业帮化简cos(2π/3-x)+cos(2π/3+x)+cosx
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 12:28:46
化简cos(2π/3-x)+cos(2π/3+x)+cosx
化简cos(2π/3-x)+cos(2π/3+x)+cosx
化简cos(2π/3-x)+cos(2π/3+x)+cosx
cos(2π/3-x)+cos(2π/3+x)+cosx
= cos(2π/3)cosx+sin(2π/3)sinx+cos(2π/3)cosx-sin(2π/3)sinx+cosx
= -cos(π/3)cosx+sin(π/3)sinx-cos(π/3)cosx-sin(π/3)sinx+cosx
= -cos(π/3)cosx-cos(π/3)cosx+cosx
= -(1/2)cosx-(1/2)cosx+cosx
= 0
cos(2π/3-x)+cos(2π/3+x)+cosx
=-cosx/2+√3/2sinx-cosx/2-√3/2sinx+cosx
=0
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