BC: 9.2 Find the discrete-time Fourier transform (DTFT) for the following sampled time signals (Hint: use the tables of DTFT pairs and DTFT properties)
a.)
x_a[n] = (0.3e^{j0.15pi})^{n+2} u[n + 3]
b.)
x_b[n] = rect((n-3)/8)
c.)
x_c[n] = rect((n-3)/8) δ[n+2]
d.)
x_d[n] = rect((n-3)/8) * ∑_{k=-∞}^{∞} δ[n-20k]
e.)
x_e[n] = (-0.2)^n cos(0.65πn) u[n]