For each of the signals given in the table below, determine whether or not it is periodic and find its period if it is. If the signal is aperiodic, enter NA for its period. Signal, a[n] Period 1 2 3 4 5 6 cos πη COS πη 12 πη 11cos (2) sin() + 7cos ( sin()+7cos(-) 12 15+ cos(²) 10 8e (n-8)/8 -9cos(7n) 16sin(8πn) - cos(3n) 9ej(n-9)/9 Periodic/Aperiodic ? ? ? ? ? ?