• in Chrome (works best): http://www.geogebra.org/chrome
• or in other browsers: http://app.geogebra.org

Today we are announcing the new Spreadsheet view in GeoGebraWeb. You now have the Algebra, Graphics and Spreadsheet view available in your web browser, all based on HTML5 without the need for any plugins. It is now also working in 44 languages (with Hindi as a new language) and variants.

Our development team is continuously working to make GeoGebraWeb better, faster and add more and more functionality of our desktop application. It would be great if you could give us feedback and suggestions in our GeoGebraWeb User Forum.

What is working now:

• Graphics, algebra, and spreadsheet view
• Tools and style bar of the graphics view
• Input bar
• Open and save ggb files, also with Google Drive

What is coming next in GeoGebraWeb:

• Right-click menus
• Properties dialogs
• CAS view
• …

Speed & Stability

As well as the usual bug-fixing and adding features, while developing version 4.2 we have rewritten large parts of GeoGebra so that it will be much more stable and also faster (much faster in some cases) than previous versions.

In particular, the following will be much faster:

• anything using the Sequence command
• the following commands when used on polynomials: Derivative/Integral/Tangent/Degree/Coefficients/Expand

Here is an example of a file using Derivative[ ] that is much faster in GeoGebra 4.2.

Here is a very nice demonstration of volume of revolution by Daniel Mentrard running in GeoGebra 4 and here is the same file in GeoGebra 4.2. Drag the red point marked “View3D” to see how much faster it is.

CAS View

The long awaited view for symbolic calculations is here. It allows you to symbolically factor, expand, differentiate or integrate expressions that may include parameters, and it is dynamically connected to all the other views. The documentation is available at http://wiki.geogebra.org/en/CAS_View.

Here is an example showing how the CAS View interacts with the Graphics View. Drag the points A, B, C to see the exact calculation of the coordinates change.

Features

The feature that’s taken the most programming time in this release is that worksheets can now be viewed on devices without Java (eg iPads, Android Tablets, Chromebooks). The best way to make use of this is to upload your applets to GeoGebraTube (File -> Share) and then the conversion will be done automatically. At the moment only the Graphics View is supported. You can test how worksheets will look and behave on tablets by adding ?mobile=true on the end of the URL in GeoGebraTube, eg
http://www.geogebratube.org/student/m20510?mobile=true

The Pen Tool has been enhanced so that it now creates a PolyLine rather than drawing to a bitmap. Together with new Delete Tool (drag a “rubber” to delete) it’s now much easier & better to use.

You can now drag a parabola, but keep its vertex fixed. Just hold down <Alt> when dragging!

The Rigid Polygon Tool has been enhanced with a small but useful feature: simply click on a polygon to make a “rigid” copy of it (ie the copy can be rotated and translated by dragging)

Neel Shah, as part of Google Summer of Code, has programmed some shape recognition algorithms for the Freehand Shape Tool, which will recognize circles, lines, line segments, triangles and quadrilaterals. It works very well on an interactive whiteboard (IWB).

You may also check a nice overview of new  features by Guillermo Bautista
and there are brief details of the hundreds of other changes in the Official Release Notes.

Power

Kai Chung Tam has programmed the PSLQ algorithm for us in Java which allows a Surd to be numerically reconstructed from a decimal. So for example SurdText[2.414213562373095] returns a nice FormulaText ie [latex]\sqrt{2}+1[/latex]. See here for an example.

We have made it much easier to make worksheets with slopefields and the particular integral like this.

All you need to type is:

f(x,y)=x/y
SlopeField[f]
A=(1,1)
Locus[A,f]

If you need more control over the spacing, there are some options, see the online manual.

Sergio Arbeo, as part of Google Summer of Code, has added a new command LocusEquation. This will calculate the equation of a (geometrical) locus using Gröbner bases.

For example here is the (numerical) locus of a parabola with the calculated (exact) locus overlaid.

Ted Kosan, a pioneer of converting computer algebra systems from different languages to others, was one of the first hard worker in this long story. Ted, the lead developer of MathPiper, also did a great effort on converting YaCAS into Java, back in 2008. Because of Reduce has been open sourced since December 2008, and a Java interface (JLisp) was also available for it, Ted decided to try to convert it to JavaScript by using the Google Web Toolkit “Java to JavaScript” compiler (GWT). His adventure was inspired by Gábor Ancsin, a former web designer, who had surprisingly great results in compiling the GeoGebra source code into JavaScript with GWT. Now Ted’s work is a part of Reduce under the name “JSLisp“, and it is also built into GeoGebra as “GGBReduce“. With Ted’s help we have been using the Java version of Reduce by inserting its bytecode stream for the desktop platform, and finally we were also able to put the same bytecode into GeoGebraWeb as a static text. (In fact, Ted was already finished with his prototype back in May 2011.)

To try it out, the user should simply go to the alpha test page of the web platform version of GeoGebra. Then enter

f(x)=x^2*sin(x)

into the input box, press ENTER, and as another command, enter

g(x)=f'(x)

In some seconds (depending on the internet connection and the machine speed, and also the browser) the output g(x)=x^2*cos(x)+2x*sin(x) will be shown in the Algebra View on the left. Google Chrome users may want to try to install GeoGebra from the Google webstore as well to make all of this work offline on their workstation, too.

Yes! No magic any longer – a full featured computer algebra system fits in HTML5 and JavaScript. The next step is to do it faster – to offer convenient use for smartphone users as well. A smartphone can be really slow, and have just limited resources, so this sounds another great challenge.