1.3 Determine whether or not each of the following signals is periodic. In case a signal is periodic, specify its fundamental period. (a) xa(t)=3 cos(5+/6) = (b) x(n) 3 cos(5n+/6) (c) x(n)=2exp[j(n/6-7)] == (d) x(n) = cos(n/8) cos(лn/8) (e) x(n) = cos(лn/2)-sin(лn/8) +3 cos(лn/4+/3)