Question 232209
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The domain is the set of values that can be taken by the independent or input variable -- generally the *[tex \Large x].


You have four ordered pairs in your set, and all of the *[tex \Large x]-coordinates are equal to 1.  Therefore the domain is *[tex \Large \{1\}].


The range is the set of all values of the dependent variable resulting from all values of the independent variable.  Therefore the range is *[tex \Large \{-2,0,3,8\}], which are the four *[tex \Large y]-coordinates.


A relation is a function if and only if every element in the domain corresponds to one and only one element in the range.  Here you have the element 1 in the domain that corresponds to 4 different elements in the range.  Not a function.  If you graphed these four points, you would find that you would be able to draw a vertical line that would contain more than one of the points (in fact, the line would contain all four points).  Any time you can find such a vertical line, your relation is NOT a function.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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