
periodic function


A function that repeats the same value at regular intervals of the variable.
A function f(x) is periodic if there exists such a number p that can make f(x+p) = f(x) for all x. The smallest p is called the period. For example, y = sin(x) is a periodic function with a period of 2 because 2 is the smallest number p that makes sin(x+p) = sin(x) for all x.

