periodic function
y = sinx <-- This is very basic periodic fuction.(period time = 2$ \pi $)
y = cosx <-- This is also very basic periodic function.(period time = 2$ \pi $)
periodic function means, The funtion repeats over and over with a period time.
non-periodic function
non-periodic function mean is opposite of periodic function. simply, The function do not reapeats over again.
$ y = x^2 $
