Definition: a Function
is called periodic with period
if for any
of the identifying numbers
and
also included in the scope and
.
Properties of periodic functions
- If the number is
a period function
, then the number
is also the period of the function. - If the function is
periodic with a period
, the function
is also periodic and its period is 
- If the function is
periodic with period
, then the composed function (function of function)
is also periodic with period
. - To plot periodic functions with the period
enough to graph on the interval length
, and then in parallel to shift this graph along the axis
at a distance
left and right.
Examples of periodic functions








a period function
is also the period of the function.
periodic with a period
is also periodic and its period is 
periodic with period
is also periodic with period
enough to graph on the interval length
at a distance
left and right.