# Definition:Real Function/Definition 1

## Definition

Let $S \subseteq \R$ be a subset of the set of real numbers $\R$.

Suppose that, for each value of the independent variable $x$ of $S$, there exists a corresponding value of the dependent variable $y$.

Then the dependent variable $y$ is a (real) function the independent variable $x$.

## Also see

• Results about real functions can be found here.