GeoGebra Tutorial 4 – Graphs and Sliders
GeoGebra is capable of graphing a variety of functions as well as computing for areas
under a curve. The screen shot below is an example of several graphs plotted in
GeoGebra.
Figure 1 - Graphs created with GeoGebra
In this tutorial, we are going to use GeoGebra to investigate the effects of parameters of
functions to its graph. Unlike in our previous activities, this time we are going to use the
Algebra window and the coordinate axes. First, we are going to investigate the graph of
by typing equations in the input field, then later, we are going to use a slider.
Graphing Functions
Open GeoGebra. We WILL need the Algebra window and the Coordinate axes so we will
NOT hide them. To un-hide the Coordinate axes, click the View menu on the menu bar,
and then click Axes. To un-hide the Algebra window, click View then click Algebra
window.
1. To graph
, type y = 2x in the input field. (The input field is the text box with the
label Input located at the bottom of your GeoGebra window.) Press the ENTER key on
your keyboard.
2. Type the following equations:
each equation.
3. Type more equations of the form
4. How does the value of
,
and,
and press the enter key after
where m is any real number.
affect the appearance of the graph of the function
?
Using Sliders
To avoid typing over and over again for varying values of parameters , we will use the
slider control. A slider is a visual representation of a number. This time, we will also add
the parameter b. This means that we will explore the graph of the function of
where
and are real numbers.
START
New
1.) Open the Geogebra window. We WILL need the Algebra window and the Coordinate axes so we
will NOT hide them. To un-hide the Coordinate axes, click the View menu on the menu bar, and
then click Axes. To un-hide the Algebra window, click View then click Algebra window.
2.) Select the Slider control and click anywhere on the drawing pad do display the Slider dialog box.
3.) In the Slider dialog box, change the slider’s name to m, change the interval to
shown below.
to
as
Figure 2 - The Slider Dialog Box
Leave the other values as is and click the Apply button to finish.
4.) Adjust the position of your slider if necessary. Move the small black circle on your slider. What
do you observe?
5.) To graph the function
, type y = m*x in the Input box.
6.) Now, move the small circle on your slider. What do you observe?
7.) Now, create a new slider and name it . Set the interval to
is.
8.) To change the function to
menu, and type y = m*x + b.
9.) Now, move your
leaving the other values as
, right click the graph, click Redefine from the context
slider. What do you observe?
10. ) How does the value of
11.) Graph the function
the function.
affect the appearance of the graph of the function
?
. Explain the effects of the parameters a and b to the graph of
Notes:
1. The ^ symbol is used for exponentiation in GeoGebra.
Hence, we write
as a*x^2 + c.
2. Instead of using
you can also use
and
in writing equations of functions,
for the function .