Which of the following signals are periodic? Determine the length of the fundamental period if it exists. a) x(t) = 3 cos (3), note that this signal is in continuous time! b) x[n] = 3 cos (3) c) x(t) = 3 cos () (continuous-time signal) d) x[n] = 3 cos (n) (Hint: plot the signal by hand or with Matlab and then use the definition of periodicity.) e) x[n] = 2 cos (n) + sin(n) f) x[n] = {...,2,0, 1, 2, 0, 1, 2, 0, 1, ...} g) x[n] = [n 4k] + [n 4k 1] =x Note: An underline (e.g. {-2,-1,0, 1, 2}) indicates the zero index of a sequence.