Evaluate each of the following functions and see if it is periodic. If periodic, find its period.
(a) f (t) = cos π t + 2 cos 3 π t + 3 cos 5 π t
(b) y(t) = sin t + 4 cos 2 π t
(c) g(t) = sin 3t cos 4t
(d) h(t) = cos2 t
(e) z(t) = 4.2 sin(0.4 π t + 10º) + 0.8 sin(0.6 π t + 50º)
(f) p(t) = 10
(g) q(t) = e−πt