Need Help with A - E in matlab

CHAPTER 5. THE DISCRETE-TIME FOURIE 90 5.1 Computing Samples of the DTFT This exercise will examine the computation of the discrete-time Fourier transform ( in MATLAB. A fundamental difference between the DTFT and the CTFT is that DTFT is periodic in frequency. Mathematically, this can be shown by examining the DTFT DTFT) equation, The DTFT is periodic with period 2 because constraining n to be an integer means that the complex exponentials ejwn are only distinct over a range of w of length 2. The principal period,-r M, then X=fft (x,N) computes N evenly spaced samples of the DTFT of x and stores these samples in the vector X. If N N 2 are also samples of X(ej") on the interval-