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^-atu(t) 

(c) x₃ (t) = e^atu(-t)

(d) x₄ (t) = (a² + t²) -1/2

(e) x₅ (t) = e^-a|t| 

(f) x₆ (t) = e^-atu(t) - e ^{-a(t -1)}u(t - 1)