## Periodic Function

A Function is said to be periodic with period if for , 2, .... For example, the Sine function is periodic with period (as well as with period , , , etc.).

The Constant Function is periodic with any period for all Nonzero Real Numbers , so there is no concept analogous to the Least Period or a Periodic Point for constant functions.

Spanier, J. and Oldham, K. B. Periodic Functions.'' Ch. 36 in An Atlas of Functions. Washington, DC: Hemisphere, pp. 343-349, 1987.