The Range of a function reference article from the English Wikipedia on 24-Jul-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Range of a function

In mathematics, the range of a function is the set of all values produced by a function. Sometimes called the image.

Given a function , the set f(A) is called the range of f. The range is not to be confused with the codomain B. Generally the range is only a subset of the codomain.

Example

Let the function f be a function on the real numbers:

defined by

The codomain of f is R, but clearly f(x) never takes negative values, and thus the range is in fact the set R⁺—non-negative reals, i.e. the interval [0,∞):

See also

codomain, function domain, injective function, surjective function, bijective function

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