Difference between revisions of "Vertical line test"

 
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A relation is a [[function]] [[iff]] no vertical line intersects the graph in more than one point.
 
A relation is a [[function]] [[iff]] no vertical line intersects the graph in more than one point.
  
For example, $y=x^2$ is a function because any vertical line intersects it in at most one point, while $x^2+y^2=1$ is not a function (try x=0).
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For example, <math>y=x^2</math> is a function because any vertical line intersects it in at most one point, while <math>x^2+y^2=1</math> is not a function (try x=0).

Revision as of 10:45, 1 July 2006

The vertical line test states that:

A relation is a function iff no vertical line intersects the graph in more than one point.

For example, $y=x^2$ is a function because any vertical line intersects it in at most one point, while $x^2+y^2=1$ is not a function (try x=0).