Tuesday, June 18, 2013

GeoGebra Tutorial: Exporting GeoGebra Worksheet to HTML 5

GeoGebra worksheets cannot run on devices that do not support Java. Examples of such devices are Apple’s iPads. To address this limitation, GeoGebra has created an export feature to HTML5. In this tutorial, we learn how to export a GeoGebra worksheet to HTML5.

Steps in Exporting a GeoGebra Worsheet to HTML5

1. Open the GeoGebra worksheet that you want to export to HTML5.   

2. Click the File menu, select Export, and then select Dynamic Worksheet as Webpage (html).


2. In the Dynamic Worksheet dialog box, select Export as Webpage button.

3. Type the Title of the web page and the texts needed above and below the construction.

4. Select the Advanced tab and be sure to check the Export to HTML only and Remove Line Breaks check boxes



5. Select File: html in the File section

6. Click the Export button


The exported HTML file can be used as a web page or embedded to websites or blogs. The HTML5 page does not need Java in order to run. 

Sunday, June 9, 2013

The Chebyshev Walking Machine

The Chebyshev linkage is a mechanical linkage that converts rotational motion to approximate straight-line motion. It was invented by the 19th century mathematician Pafnuty Chebyshev who studied theoretical problems in kinematic mechanisms.



One of these linkages is shown above. It is called the Chebyshev walking machine. Notice that the mechanism seems to reproduce the legs of an animal. Click the Play button to start the animation.

Snapshot

Reference
"Chebyshev Walking Machine"
 http://demonstrations.wolfram.com/ChebyshevWalkingMachine/
 Wolfram Demonstrations Project
 Published: November 5, 2012

Wednesday, April 10, 2013

Five Squares to One

Move points A and B to resize the squares. Drag the slider to the extreme right to move the parts of the square. This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com
Snapshot


Contributed by: Izidor Hafner

Monday, March 25, 2013

Dissecting an Octagon to Two Smaller Octagons

To dissect the octagon, move slider alpha to the extreme right and then move slider v to the extreme right.
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com
Reference:

Contributed by: Izidor Hafner
Based on work by: Greg N. Frederickson


Snapshot

Monday, February 25, 2013

Multiplication Table

Move the Column and Row sliders to choose the numbers you want to multiply.

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com
Snapshot
 

Tuesday, February 5, 2013

GeoGebra Tutorial: How to change the x-interval to pi or pi/2

In graphing Trigonometric Functions, there are cases that you need to change the interval of the x-axis in terms of π.  In this tutorial, you will learn how to change the interval of the x-axis. 

1.) Right click a blank space on the Graphics view and then click on Graphics... from the pop-up menu to display the Preferences dialog box.

2.) In the Preferences dialog box, click on the xAxis tab, and then check the Distance check box.
.


3.) In the drop-down list box at the right of the Distance check box, select π or π/2 and then click the Close button to close the dialog box.

After step 3, the interval of the x-axis should be π or π/2.



Monday, January 21, 2013

Cross to Isosceles Triangle Dissection

Move the Size slider to change the size of the cross and move the slider alpha to the extreme right to transform the figure. 
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

The applet above is an example of a dissection puzzle. A dissection puzzle, also called a transformation puzzle tiling puzzle where a set of pieces can be assembled in different ways to produce two or more distinct geometric shapes (Wikipedia). 

The cross to isosceles triangle dissection puzzle above was created by Henry Dudeney in 1897.

Snapshot



Reference
"Dudeney's Cross-to-Isosceles-Right-Triangle Dissection" from the Wolfram Demonstrations Project
 http://demonstrations.wolfram.com/DudeneysCrossToIsoscelesRightTriangleDissection/

Wednesday, January 16, 2013

Folding an Ellipse

Paper Folding Activity

1. Draw a circle and draw a point in its interior.
2. Mark a point anywhere on the circle.
3. Fold such that the two points coincide and crease well.
4. Repeat steps 2-3 as many times as you can.

What do you observer about the creases?

Click the Play button on the bottom-left of the applet to simulate the paper folding activity above.
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com
Note: The green lines represents the folds on the circle.

Shapshot


Thursday, January 10, 2013

GeoGebra Tutorial: Constructing a Cardioid

A cardioid is a curve formed by moving circles. One of the ways to form a cardioid is shown below. In the applet (move the slider to the extreme right), the cardioid is given as the envelope of circles whose centers lie on a given circle and which pass through a fixed point on the given circle. 


This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Step by Step Instruction in Constructing the Applet Above

1. Construct point A at (0,0) and point B at (0,1).
2. Construct a circle with center A and passing through B
3. Construct an angle slider and set the minimum number to 0°, maximum number to 360° degrees and increment of 2°.  
4. Construct angle BAB'. To do this, select the Angle with Given Size tool, click on point B and click on point A to display the Angle with Given Size dialog box. 
5. In the Angle with Given Size dialog box, replace 45° with α,  choose counterclockwise button, and then click OK. 
6. Hide the green sector by right clicking it and then clicking on the Show Object from the pop up menu.
7. Now construct a circle with center B' and passing through B.
8. Right click the circle with center B and  click Trace on. 
9. Move the slider and observe what happens. 

Snapshot

Wednesday, January 2, 2013

GeoGebra Tutorial: How to Disable Reflex Angles


In GeoGebra, we use the Angle tool to reveal angle measures.  By default, an angle can measure  up to 360°; howeverthere are instances that we want it to be less than or equal to 180°.  For example, we need to limit the angle measures of the interior angles of a polygon to 180° if we want to find its angle sum. 






In this tutorial, we learn how to disable angles measuring more than 180° but less than 360°.  Such angles are called reflex angles.  To disable reflex angles, do the following:

1. Right click the angle measure (green sector) and click Object Properties to display the Preferences window.


2. In the Preferences window, click the Basic tab.
3. Select 0° and 180° in the Angle Between dialog box and then close the window.