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 which the function is defined.

That is, the function provides an "output" or value for each member of the domain.

Description

Conversely, the set of values the function takes on as output is termed the image of the function, which is sometimes also referred to as the range of the function.

For instance, the domain of cosine is the set of all real numbers, while the domain of the square root consists only of numbers greater than or equal to 0 (ignoring complex numbers in both cases). When the domain of a function is a subset of the real numbers, and the function is represented in an xy Cartesian coordinate system, the domain is represented on the x-axis.

See also

• Bijection, injection, and surjection
• Codomain
• Domain decomposition
• Effective domain
• Lipschitz domain
• Naive set theory
• Range (mathematics)

External links

• Domain of a function @ Wikipedia.org