C. Vertical Line Test
When a relation is graphed, there is a visual test that can be done to determine whether or not it is also a function. The test is called the vertical line test. If a vertical line can be drawn anywhere on the graph and it passes through more than one point, the graph does not represent a function. In a function, the vertical line passes through the output value(s) corresponding to a single input value. If the line passes through more than one output value, the relation cannot be a function.
The vertical line test can be performed by actually drawing vertical lines or by placing a pen/pencil in a vertical line on top of the graph.
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Vertical Line Test
a visual way to determine if a relation is a function or not |
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Example 3 |
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Use the vertical line test to determine which of the following relations are also functions.
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