![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cfdcb7614e721aa6561debca55f3b7d5.png\")
, it touches the graph at ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b7daefc4cbcd0ceb1714205137ac1c4b.png\")
. \
Vertical Line Test :
\A collection of points is the graph of a function provided that every vertical line
\intersects the graph in at most one point.
\\
Consider the vertical line at , it touches the graph at .
The graph does not satisfy the vertical line test.
\Thus, the graph is not a function.
\\
The graph is not a function.