三角恒等变换证明cosx+cos2x+…+cosnx=[cos(n+1/2)·sinnx/2]/sinx/2怎么证明?
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 19:01:52
![三角恒等变换证明cosx+cos2x+…+cosnx=[cos(n+1/2)·sinnx/2]/sinx/2怎么证明?](/uploads/image/z/2767015-55-5.jpg?t=%E4%B8%89%E8%A7%92%E6%81%92%E7%AD%89%E5%8F%98%E6%8D%A2%E8%AF%81%E6%98%8Ecosx%2Bcos2x%2B%E2%80%A6%2Bcosnx%3D%5Bcos%EF%BC%88n%2B1%2F2%EF%BC%89%C2%B7sinnx%2F2%5D%2Fsinx%2F2%E6%80%8E%E4%B9%88%E8%AF%81%E6%98%8E%3F)
xPJ@Cąr32X&R'mJT&i?̝W'n7\8/5mUSQOnd8js/o7nl)X4kX4Gc"cE!(*`=D/?u,?m~,^YuϽKYpv;cM嬆^y]"C*=3=*SOq4l
ect:kߊ.JJe&rl/=
三角恒等变换证明cosx+cos2x+…+cosnx=[cos(n+1/2)·sinnx/2]/sinx/2怎么证明?
三角恒等变换证明
cosx+cos2x+…+cosnx=[cos(n+1/2)·sinnx/2]/sinx/2
怎么证明?
三角恒等变换证明cosx+cos2x+…+cosnx=[cos(n+1/2)·sinnx/2]/sinx/2怎么证明?
说个思路啊,用2sinx/2分别乘以等式左边各项,然后用积化和差公式,最后发现有好多项消去了.最后就得你要的东西了.