What is the Vertical Line Test for Functions?
Answer: A method to distinguish functions from relations.
The vertical Line test.
- is a way to determine if a relation is a function.
- states that if a vertical line intersects the graph of the relation more than once, then the relation is a NOT a function.
If you think about it, the vertical line test is simply a restatement of the definition of a function.
Definition of a function: Every x value has a unique y value.
Think about it If any particular x value has 2 different y values, then a vertical line will intersect the at two different places.
Let's examine the two relations below this These two relations differ by only 1 number!