A constant function is a function which has a constant output: the value of the function does not depend on the value of its input. Equivalently, a constant function is a function whose range has only a single value. For example, is a constant function because always equals , and is a constant function since is always equal to . So, basically, a constant function is a function that for whatever input you put in, it always returns the same value, or a constant.
This article is a stub. Help us out by expanding it.