# Whistler: Create An Applet

These four applets are designed to demonstrate the interactive functionality of building an applet, rather than demonstrating the cool math that GeoGebra can do. You can always use other math more relevant to your classes. The creative potential is immense, and one must choose one place to begin and get going.

Videos are taken using GeoGebra Classic 5 downloaded. The online app is very similar but not the same. There are no verbal instructions on the videos, just demonstrations of where to go to get what. I found that verbal instructions led to incredibly wieldy videos.

# 1. A starter applet

Create some math

Button to update construction

Whistler Applet 1 Written instructions

Whistler Applet 1 Video Demonstration

# 2. Construction

Here’s a blank workspace that allows users limited tools. Could be used in conjunction classic constructions such as these ones on mathisfun.

Go ahead and draw an equilateral triangle. Use the measuring tools only when completed.

The point of putting this applet here is to demonstrate how to control the toolbar, and to discuss the other various options when uploading an applet.

Whistler Applet 2 Construction adjusted tool bar

Whistler Applet 2 Video demonstration

# 3. Demonstrating A Construction with the Construction Protocol

Here we demonstrate how a square, possibly a little elaborate, might be drawn with a straight edge and compass. On your applet, choose any construction or drawing you feel like making with the tools available.

On your own applet, after completing your construction delete any objects that you don’t want to be seen at all and make visible all the other objects. Turn on the construction ‘navigation bar’. To do that, find the graphics preferences menu (right click on empty space on the graphics screen, choose graphics), and check the navigation as below:

# 4. Multiplication with add ons

Features:

Input box for ‘how many correct’

Correct Bar

Celebrate reaching the goal

Start Over button

(I use, ‘how many correct’ for some classes, but ‘how many correct in a row’ for others).

Whistler 4 Multiply with Add Ons Written Instructions

Whistler Applet 4 Video demonstration

# 5. Parabola Match

What’s new here:

2 windows

Setting up a function with carefully selected random parameters.

Written instructions: Whistler Applet 5 Parabola Match

# Other videos

Drawing Sinusoidal Curves, Radians, Degrees etc

Drawing a 24 Point Circle, using the spreadsheet to generate points (same idea for modelling)

GeoGebra have their own you tube channel – link on the next page.

# Top tips: Just to save you a one or two or many hours:

If, on an applet, you wish to have ‘show trace’. To clear the trace, the script required is ZoomIn[1]

The ‘Fit’ command for modelling data. Import or enter a data set to the spreadsheet. Select data, right click, create, list of points. Then use the ‘fit’ command and choose from the various options.

The round command – rounds to the nearest integer. On the trigonometry applets, I have taken the calculator answer, multiplied by 100, used the round command, then divided by 100. This will allow students to round to 2 d.p.

CAS commands – Geogebra doesn’t identify equivalent expressions of different forms as distinct. For example, the factored trinomial applet will say that any equivalent expression is correct. You’ve got to decide if you want to manufacture around this or not.

When entering a function with random parameters, such as f(x)=ax+b, where a is any value between -10 and 10; it is nice to use the ‘simplify’ command so that your function presents well. Without the simplify, it might read, . With simplify, it reads .