A function is said to be periodic if its values repeat at regular intervals. More precisely, a function is said to be periodic if, there exist a nonzero constant such that
for all values of
in the . The constant
is called the period
or fundamental period
of the function, if it is the smallest positive real number satisfying the condition shown above.
A well known example of periodic functions are the which have a period of
Some examples are shown below.
Here, the arguments of the tigonometric functions is in radians not in degrees.