Consider an analog periodic sinusoid x(t) = cos (3t + /4) being sampled using a sampling period

Consider an analog periodic sinusoid x(t) = cos (3πt + π/4) being sampled using a sampling period T_s to obtain the discrete-time signal x[n] = x(t)|_t=nTs = cos(3πT_s n + π/4).

(a) Determine the discrete frequency of x[n]

(b) For what values of T_s is the discrete-time signal x[n] periodic? Let T_s = 1/3, use function stem to plot x[n], 0 ≤ n ≤ 100 and determine if it is period. Let T_s = 1\π, use function stem to plot x[n], 0 ≤ n ≤ 100 and determine if it is periodic.