Vertical Line Test

Vertical Line Test

Goal: To identify functions using the vertical line test.

​Functions

Recall that functions are relations where every "x" value has just one "y" value. This means that the line of every graphed function will have (x, y) coordinates where no "x" is associated with more than one "y". So if we could imagine drawing a vertical line anywhere along a graphed function, our vertical line would not cross the function more than once.

Subject | Subject

Some text here about the topic of discussion

Multiple Choice

In a function how many y-values can be associated with a single x-value?

• 0

• 1

• 2

• 3

Notice the graphed equation on the left can only be crossed once, making it a function. At the same time the graphed equation on the right could be crossed twice by a vertical line, meaning it cannot be a function.

​

​Some text here about the topic of discussion.

​Comparison:

Notice how the one of the imaginary dotted lines crosses the graphed equation more than once?

That means this is not a function.​

​

​Some text here about the topic of discussion.

​Example:

Notice how the imaginary dotted line crosses the graphed equation only once?

That means this is a function.​

​

​Some text here about the topic of discussion.

​Example:

Multiple Choice

How many of the graphed equations is a function?

• 4

• 1

• 2

• 3

• 0

Multiple Choice

How many of the graphed equations are functions?

• 1

• 2

• 4

• 3

• 0

Multiple Choice

Is the graphed equation a function or relation?

• Function

• Relation

Multiple Choice

Is the graphed equation a function or relation?

• Function

• Relation

Draw

Draw a graphed equation, as a function.