Domain and Range of FunctionsDate: 03/20/2003 at 20:35:32 From: Jimmy Neutron Subject: Domain and range I am learning in school about the domain and range of functions. Why are they called domain and range? And where did they come from? Date: 03/20/2003 at 23:37:05 From: Doctor Peterson Subject: Re: Domain and range Hi, Jimmy. "Domain" and "range" are just two different words for "how far something extends"; specifically, a king's domain is the territory he controls, and an animal's range is the region it wanders through. So it makes some sense that the set of numbers a function "controls" would be called its domain, and the set through which its value can wander is called its range. To be more precise, Merriam-Webster, at m-w.com, defines the words (in the most relevant usage) this way: Domain 2 : a territory over which dominion is exercised 5 : the set of elements to which a mathematical or logical variable is limited; specifically : the set on which a function is defined (The word comes from the Latin word for "lordship".) Range 3 a : a place that may be ranged over b : an open region over which animals (as livestock) may roam and feed c : the region throughout which a kind of organism or ecological community naturally lives or occurs 8 a : the set of values a function may take on b : the class of admissible values of a variable (Several other uses are similar, such as the range of a weapon or a voice; the original meaning comes from the idea of animals ranging about.) If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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