Range

Revision as of 09:24, 6 July 2006 by JBL (talk | contribs)

Let $A$ and $B$ be any sets, and let $f:A\to B$ be any function. Then $\{b\in B\mid \mathrm{there\ is\ some\ } a\in A\mathrm{\ such\ that\ } f(a)=b\}$ is called the range or image of $f$.

Thus, if we have $f: \mathbb{R} \to \mathbb{R}$ given by $f(x) = x^2$, the range of $f$ is the set of nonnegative reals.