*Macmillan Science Library: Mathematics*. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.

This section contains 504 words(approx. 2 pages at 300 words per page) |

## Functions and Equations

In mathematics, function is a central idea. Imagine a machine that takes numbered balls from 1 through 26 and labels them with the English alphabet letters A through Z. This machine mimics a mathematical function. A function takes an object from one set ** A** (the input) and maps it to an object in another set

**(the output). In mathematics,**

*B***and**

*A***are usually sets of numbers. In symbols, this relationship is written as**

*B**f*:

**→**

*A***.**

*B*So, a function *f* is the name of a relationship between two sets. Functions are usually denoted by the letters *f, g,* or *h.* ** A** is called the

**domain**(input), and

**is called the**

*B***range**(output). If the elements of the domain are denoted by

*x*, and the elements of the range are denoted by

*y*, then a function can also be written as

*y*=

*f...*

This section contains 504 words(approx. 2 pages at 300 words per page) |