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Domain Of A Function




In Mathematics , the domain of a Function is the set of all input values to the function.


DOMAIN OF A FUNCTION

Given a function ''f'':''X''→''Y'', the set ''X'' of input values is called the Domain of ''f'', and ''Y'', the set of possible output values, is called the Codomain . The Range of ''f'' is the set of all '''actual''' outputs {''f''(''x'') : ''x'' in the domain}. Sometimes the codomain is incorrectly called the range because of a failure to distinguish between possible and actual values.

A well-defined function must map every element of the domain to an element of its codomain. For example, the function ''f'' defined by
: ''f''(''x'') = 1/''x''
has no value for ''f''(0).
Thus, the set R of Real Number s cannot be its domain.
In cases like this, the function is usually either defined on R\{0}, or the "gap" is plugged by specifically defining ''f''(0).
If we extend the definition of ''f'' to
: ''f''(''x'') = 1/''x'', for ''x'' ≠ 0
: ''f''(0) = 0,
then ''f'' is defined for all real numbers and we can choose its domain to be R.

Any function can be restricted to a Subset of its domain.
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