Relations and Functions
(Vertical Line Test)

Andymath.com features free videos, notes, and practice problems with answers! Printable pages make math easy. Are you ready to be a mathmagician?

Notes

Notes for Functions


Problems & Videos

\(\textbf{1)}\) \(\text{Does this represent a function? } {(1{,}2),(2{,}4),(2{,}5),(5{,}8)} \)Link to Youtube Video Solving Question Number 1


\(\textbf{2)}\) Does this represent a function?
Graph for Question 2Link to Youtube Video Solving Question Number 2


\(\textbf{3)}\) Does this represent a function?
Graph for Question 3Link to Youtube Video Solving Question Number 3


For problems \(3-9\), use \(f(x)=3x+5\). Find the following.

\(\textbf{4)}\) \(f(5)\) Link to Youtube Video Solving Question Number 4


\(\textbf{5)}\) \(f(-4)\) Link to Youtube Video Solving Question Number 5


\(\textbf{6)}\) \(f(0)\) Link to Youtube Video Solving Question Number 6


\(\textbf{7)}\) \(f(y)\) Link to Youtube Video Solving Question Number 7


\(\textbf{8)}\) \(f(2z)\)Link to Youtube Video Solving Question Number 8


In Summary

The vertical line test is a graphical method used to determine whether a curve in the plane represents the graph of a function. The test is performed by drawing a vertical line anywhere on the graph and observing the number of times that the line intersects the curve.

If the line intersects the curve in exactly one point, then the curve represents the graph of a function. This is because a function must have exactly one output value for each input value, and a vertical line can only intersect a graph in one point if the graph represents a function.

On the other hand, if the vertical line intersects the curve in more than one point, then the curve does not represent the graph of a function. This is because a function cannot have more than one output value for a given input value, and a vertical line that intersects a graph in multiple points indicates that the graph does not represent a function.

The vertical line test is a simple and effective method for determining whether a curve in the plane represents the graph of a function. It is based on the fundamental property of functions that they must have exactly one output value for each input value.

About Andymath.com

Andymath.com is a free math website with the mission of helping students, teachers and tutors find helpful notes, useful sample problems with answers including step by step solutions, and other related materials to supplement classroom learning. If you have any requests for additional content, please contact Andy at tutoring@andymath.com. He will promptly add the content.

Topics cover Elementary Math, Middle School, Algebra, Geometry, Algebra 2/Pre-calculus/Trig, Calculus and Probability/Statistics. In the future, I hope to add Physics and Linear Algebra content.

Visit me on Youtube, Tiktok, Instagram and Facebook. Andymath content has a unique approach to presenting mathematics. The clear explanations, strong visuals mixed with dry humor regularly get millions of views. We are open to collaborations of all types, please contact Andy at tutoring@andymath.com for all enquiries. To offer financial support, visit my Patreon page. Let’s help students understand the math way of thinking!

Thank you for visiting. How exciting!