I don't know how to solve (a),(b),(e) problems. Program 3_1 matlab code is below. please help me.

% Program 3_1 % Discrete-Time Fourier Transform Computation % % Read in the desired length of DFT k = input('Number of frequency points = '); % Read in the numerator and denominator coefficients num = input('Numerator coefficients = '); den = input('Denominator coefficients = '); % Compute the frequency response w = 0:pi/k:pi; h = freqz(num, den, w); % Plot the frequency response subplot(2,2,1) plot(w/pi,real(h));grid title('Real part') xlabel('\omega/\pi'); ylabel('Amplitude') subplot(2,2,2) plot(w/pi,imag(h));grid title('Imaginary part') xlabel('\omega/\pi'); ylabel('Amplitude') subplot(2,2,3) plot(w/pi,abs(h));grid title('Magnitude Spectrum') xlabel('\omega/\pi'); ylabel('Magnitude') subplot(2,2,4) plot(w/pi,angle(h));grid title('Phase Spectrum') xlabel('\omega/\pi'); ylabel('Phase, radians')

M 3.2 Using Program 3 I. determine and plot the real and imaginary parts and the magnitude and phase spectra of the IOTFI s of the sequences of Problem 3.19 for N 10, 3.19 Determine the DTFT of each of the following finite-length sequences: (a) yiln 1. -N S n S N 1, 0 s n s N 0, otherwise, (b) y2In) otherwise, -N s n s N (c) y3[n] otherwise, N n N cos (Trn/2N) N S n s N (d) y4 (e) y fInl otherwise, otherwise