Sketch the following signals: (a) x(t) = u(t + 1) 2u(t 1) + u(1-3) (b) x(t) = (t + 1)u(t - 1) - tu(t) - u(1-2) (c) x(t) = 2(t-1)u(t-1)-2(12)(1-2) + 2(1 - 3)u(1-3) (d) Use MATLAB to plot the signals defined in parts (a) to (c). Plot the following discrete-time signals: (a) x[n] = (0.5) u[n] (b) x[n] = (-0.5)n u[n] (c) x[n1 = 2 u[n] (d) x[n] = sin( n/4) (e) x[n] =sin( n/2) (f) x[n] = (0.9) [sin(n7/4) + cos(7/4)] (g) Use MATLAB to plot the above signals