# Real Function/Examples/Arbitrary Function

## Example of Real Function

Let $f$ denote the real function defined as follows:

$\map f x = \begin {cases} 2 & : 0 \le x \le 1 \\ \sqrt x & : 2 \le x \le 3 \end {cases}$

Thus the domain of $f$ is seen to be:

$\Dom f = \closedint 0 1 \cup \closedint 2 3$