Find the normalized power for each signal below that is a power signal and the normalized energy for each signal that is an energy signal. If a signal is neither a power signal nor an energy signal, so designate it. Sketch each signal (α is a positive constant).
(a) x1 (t) = 2 cos(4πt + 2π/3)
(b) x2 (t) = e-αtu(t)
(c) x3 (t) = eαtu(-t)
(d) x4 (t) = (a^2 + t^2)^(-1/2)
(e) x5 (t) = e-α|t|
(f) x6 (t) = e-αtu(t) - e -α(t -1)u(t - 1)