How to Graph Quadratics Using Geogebra
From a Table of Values:
1. View
2. Spreadsheet
3. Input values of table as A (x) and B (y)
4. Highlight inputted A and B values
5. Go to the second box from the top left and select Two Variable Regression Analysis
6. Select Analyze on the window that pops up.
Now you will have a scatterplot without any line. To show the regression (actual line of quadratic):
7. Select Polynomial in drop down menu under Regression Model on the bottom left of the graph window.
From an Equation:
Use the input bar at the bottom of the Geogebra Graphics page and write the equation exactly as it appears with one
small change: you must write as x^2 on Geogebra. You get the little “hat” by pressing shift+6.
How to Find the Vertex and Roots (x-intercept) on Geogebra
Make sure that you are able to view the Algebra Window (if you cannot go to View-> Algebra)
Option 1: Using the Point Function
1. Select the Point function (this is the second box from the top left)
2. Click anywhere on the quadratic. This will create a point.
3. Now, you can drag the point you’ve created anywhere along the quadratic. Including to its roots and vertex!
Option 2: Using the Vertex and Root Commands
(use this if you need to find exact values (especially for the vertex))
Roots:
1. In the input bar, type “Root” and select the “Root[<Polynomial>]” command
2. Type the equation for your quadratic (e.g.,
) into the <Polynomial> section of the command
3. The points for the roots will appear in the Algebra Window
Vertex:
1. In the input bar, type “Extremum” and select the “Extremum[<Polynomial>]” command
2. Type the equation for your quadratic (e.g.,
) into the <Polynomial> section of the command
3. The vertex point will appear in the Algebra Window