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Geometry Expressions Newsletter
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Geometry Expressions NewsletterJune 2012  
Geometry Expressions 3.0 SP2
We have just released a free upgrade to Geometry Expressions version 3.0. 

A major feature of this release is the ability to export Dashboard Widgets which can be incorporated in iBooks for the iPad using Apple's iBook Author software.  This lets you embed interactive mathematical diagrams in your iBook.
Pythagoras proof
Sample iBooks with interactive components generated by Geometry Expressions can be downloaded here.

Other new features of the release are: 
  • Ability to drag a point along a line or curve in a generated JavaScript app.  
  • Multitouch support for JavaScript apps. 
  • Lua source code generation.
  • Background color.
  • Graph windows with independent scaling of x and y axes.
  • Setting precision of numeric outputs either as fixed number of digits or fixed number of decimal places 

For technical reasons, the automated updater may not update your copy of Geometry Expressions to this new version.  To update, download a patch file from here


If you have Geometry Expressions version 1, or 2, simply upgrade to version 3, and you will receive the new version. 

How to...write an iBook with Geometry Expressions
Well, you actually write the iBook with Apple's iBooks Author software, which is a free download from the Mac App Store.  But you use Geometry Expressions to create interactive elements which you can incorporate in your iBook.  Here's how.

First create your model inside Geometry Expressions, bearing the following in mind:
  • Points which you want to be freely draggable should have coordinate constraints, with the coordinates specified as variables.
  • Points which should drag along a curve or line should be constrained using the point proportional constraint, and its value should be set as a variable.
  • Only symbolic measurements will be available for output.  
Now do File/Export/Os X Dashboard Widget.
Widget Dialog
A dialog appears which lets you add a title, some text above and below the diagram, and lets you specify which variables are accessible to the user and in what form.

Inserting the Widget in your iBook is easy.  In iBooks Author, do


You can then choose the widget and add a caption.

Problem of the Month
triangle sectors
Triangle ABC is isosceles.

When is sector ACF inside the triangle?

When does sector ACF have the same area as sector CED?

What is the largest circular sector which lies entirely inside ABC?

An interactive app which lets you play with this problem is here.
Electronic Book Bundle

10 Geometry Expressions eBooks are now available as a bundle for the recession-friendly price of $79.95
Bundle includes:
  1. The Tortoise and Achilles
  2. Calculus Explorations  
  3. The Farmer and the Mathematician
  4. Developing Geometry Proofs  
  5. 101 Symbolic Geometry Examples
  6. 101 Conic Sections Examples  
  7. Using Symbolic Geometry to Teach Secondary School Mathematics  
  8. Connecting Algebra and Geometry through Technology
  9. Function Transformations
  10. Exploring with Geometry Expressions 

Learning Calculus with Geometry Expressions is a unique electronic resource containing lecture-ready slides and lab-ready Geometry Expressions files.
Available for $6.99 per chapter, or $34.95 for the whole book.

See our YouTube channel for videos exploring features in Geometry Expressions.

Phil Todd's TechIgnite talk connects central pivot irrigation in Texas to Malfatti's Problem
Quick Links
Geometry Expressions
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