en.wikipedia.org/wiki/Domain_of_a_function

In mathematics, and more specifically in naive set theory, the domain of definition
(or simply the domain) of a function is the set of "input" or argument values for ...

www.khanacademy.org/math/algebra/algebra-functions/domain-and-range/v/domain-of-a-function-intro

Jun 25, 2015 ... Sal introduces the concept of "domain" of a function and gives various examples
for functions and their domains.

www.coolmath.com/algebra/15-functions/06-finding-the-domain-01

OK, so suppose we don't have the graph of a function to look at like in the last
section... Can we still find the domain and range?

www.purplemath.com/modules/fcns2.htm

These won't be terribly useful or interesting functions and relations, but your text
wants you to get the idea of what the domain and range of a function are.

www.intmath.com/functions-and-graphs/2a-domain-and-range.php

Oct 18, 2016 ... We learn the domain of a function is the set of possible x-values and the ... The
curve goes on forever vertically, beyond what is shown on the ...

www.mathsisfun.com/definitions/domain-of-a-function.html

All the values that go into a function. The output values are called the range.
Domain → Function → Range Example: when the function f(x) = x<sup>2</sup> is given the ...

www.basic-mathematics.com/domain-of-a-function.html

Domain of a function. To understand what the domain of a function is, it is
important to understand what an ordered pair is. ... What is the domain of (6x + 7)/
x - 5

www.wikihow.com/Find-the-Domain-of-a-Function

The domain of a function is the set of numbers that can go in to a given function.
In other words, it ... What is the domain of the function y = x + sqrt(x) + 1? Atheia.

www.reference.com/math/domain-function-ac59a251220abca0

The domain of a function is all of the x values of the function without any
repetition. A vertical line has only one x value as its domain, while a horizontal
line has a ...

www.freemathhelp.com/domain-range.html

When working with functions, we frequently come across two terms: DOMAIN &
RANGE. What is a domain? What is a range? Why are they important?