Function

In [[Mathematics]], a means of associating two (or more) quantities (or variables). Each variable has a disinctive role.
#The ''independent variable'' is a value selected from a set called the ''domain'' of the function.
#The ''dependent variable'' is a value (in a set called the ''range'' of the function) which is determined by the value of
the independent variable.


#A function may be specified by giving an ''algorithm'' (or rule) which yields the value of the dependent variable when the value of the independent variable is provided as input.
#A function may be specified by a  of ''ordered pairs'' of values.
#A function may be described by a ''graph of points'' in two dimensions presenting (conventionally) the independent variable as the horizontal component and the dependent variable as the vertical component.

The concept of a function has been generalized to include arbitrary domains and ranges, the most common on which is the ''vector valued function'' in which the range is a set, not of numbers, but of ''n-tuples'' or vectors.
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[[Dick Beldin]]