A three-phase voltage source inverter used for distribution system tested with following signals. Check whether the signals are periodic or not. It is periodic, find the fundamental time period T. a....

A three-phase voltage source inverter used for distribution system tested with following signals. Check whether the signals are periodic or not. It is periodic, find the fundamental time period T.
a. x(t)=cos⁡(t/8)+cos⁡(πt/8)
b. x(t)=e^(j(3πt/8))
c. x(t)=sin⁡(3πt)