CT Periodic Fx
$ x(t)=e^j*t $
$ e^j*t $---> $ cos(t) + j*sin(t) $
the real part is periodic along with the imaginary part
DT Periodic Fx
$ x[n]=e^j*w*n $
the value will be periodic as long as
$ w/(2*pi) = K/N $
K is any integer
CT NON-Periodic Fx
$ x(t)=x^2 $
does not follow the rules for periodic signals
