Difference between revisions of "Vertical line test"

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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 the line <math>x=0</math>).
 
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 the line <math>x=0</math>).
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In other words, for every x value, there should only be one y value.
  
 
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Revision as of 00:33, 25 May 2016

The vertical line test is a way of determining whether or not a plotted graph is a function.

The vertical line test states that a relation is a function iff no vertical line intersects the graph in more than one point.

This is because a function cannot have more than one output for any one input.

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 the line $x=0$).

In other words, for every x value, there should only be one y value.

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