Determine whether or not each of the following signals is periodic. if a signal is periodic, determine its fundamental period:
a. X[n] = eʲ ((n/4) - π))
b. X[n] = cos (n/2) cos(πn/4)
c. X[n] = cos (πn/4) + sin (πn/8) - 2 cos (πn/2)