Note: for all continuous time signals x(t), time t = R; for all discrete time signals x[k], time index k Z. (a) Plot the magnitude and phase spectrums of the following discrete time signal k x[k] = cos( +sin( 2 (b) Compute DTFT of the following signals with x[k] defined in (a). [k] = x[k] * x[k] k. g[k] = (1 + cos())x[k] h[k] = -k (3)* step(k + 1)