Let T be the N-by-N discrete Fourier transform matrix. why does T inverse = NT*, where T* is the conjugate transpose of T?

17. Let T be the N-by-N discrete Fourier transform matrix, i.e. entries To = ~WN", where We is j-th of N roots of unity. Prove that T-1 = NT*, where T* is the conjugate transpose of T. 18. Below you are given the plot of the DFT of some data f[n]. The sampling frequency is Fs = 6. Classify the aliases and explain your reasoning. IF[K]I + K -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7