## Real Functions: Identity Function

An identity function is a function that always returns the same value as its argument. In other words, the identity function is the function

*f*(

*x*) =

*x.*

A sampling of data for the identity function is presented in tabular form below:

x | −999 | −10 | 0 | π | 5 | 100 | 9999 |

f (x) | −999 | −10 | 0 | π | 5 | 100 | 9999 |

Additionally, graphical representation of the identity function is depicted below: