各位大神，帮帮我证明下这个傅里叶公式吧~~急！谢谢了

liluxiang333

原话是这样的，就说了这个能被傅里叶公式证明可是，具体怎么证明没写，我数学不好~~跪求各路大神相助！
引号里大致的意思就是：任意一条2π周期曲线可以被表示成傅里叶级数，当曲线在时域平移n次，每次360°/n，
则曲线的平均值转换成傅里叶图后，仅剩下n及n倍数的分量。
Here, we use the law of the Fourier series written in the following
that can be mathematically proved about arbitrary periodic curve,
“An arbitrary periodic curve of 2π can be expressed by the
Fourier series, and when n-number of curves with a phase
shift of 2π/n at a time are averaged, the averaged curve
shows the sum of an integral multiple of n-order Fourier
components of the original curve”.

liluxiang333

附带的两幅图，一副是表示一个信号相移了7次，最底下那条是平均的结果。右边傅里叶图是平均的结果作傅里叶变换得到的

liluxiang333

sos000000