When given a graph, the vertical line test can be used to

determine functionality. Describe the vertical line test and

explain the reasons why a graph would, or would not,

represent a function.

Intro

The vertical line test can be used to determine whether a graph represents a function. If we can draw any vertical line that intersects a graph more than once, then the graph does not define a function because a function has only one output value for each input value.