Author: Ton Lecluse 

    Investigating a function



The construction box
Plane geometry
Investigating a section
Investigating a function
Drawing in perspective
A probability tree
The calculator
Getting a taste
Back to start


This exercise requires you to set the difficulty level to intermediate in the configuration window.

You should start with an existing drawing. Click file, open or click the open folder button . Open the “parabola with parameter” file, you will find it in the DEMO folder. The parabola y = x˛ will appear in the co-ordinate system.


Now, right-click this graph and a menu with one single line will appear. Click it and the menu will extend. You should choose the following: “animated analysis”, “investigate parameter”.



A (parameter) control box will pop up. The factor is listed before x and can be changed manually causing the parameter to change. (The number on the first line will either be added to or subtracted from the number on the second line. You can decide whether to increase or decrease the number.)

Changing the parameter will automatically and almost instantly result in a change in the drawing.

The bottom line of the control box displays the function formula as a whole once more.

In the drawing on the left, the parameter has been made negative. You can see how the original upward opening parabola changes to a downward opening parabola.
Two functions are now present and this is illustrated by the two radio buttons below the two little hands. You are now working on the first (green) function.

  Should you click on button number two, you will continue working with the second (red) function. You can now move it horizontally or vertically. The function is f (x) = (x – a)˛ + b and it contains two parameters. Geocadabra allows you to define functions yourself and these functions can consist of up to 4 parameters.

You can investigate even more functions. Why not explore the possibilities by right-clicking on one of the functions and scan the options in the presented menu?