Determine whether the follow signals are period and for those that are find the fundamental period.
F: x(t) = cos(t)u(t)
G: x(t) = v(t) + v(-t)
where v(t) = cos(t)u(t)
H: x(t) = v(t) + v(-t)
where v(t) = sin(t)u(t)
I: x[n] = cos((1/5)(pi)(n)) * sin((1/3)(pi)(n))