GeoGebra

GeoGebra is an interactive geometry, algebra, and calculus application, intended for teachers and students. Most parts of GeoGebra are free software. GeoGebra is written in Java and thus available for multiple platforms. Many parts of GeoGebra have been ported to HTML5 by using the Google Web Toolkit.

Its creator, Markus Hohenwarter, started the project in 2001 at the University of Salzburg, continuing it at Florida Atlantic University (2006–2008), Florida State University (2008–2009), and now at the University of Linz together with the help of open-source developers and translators all over the world. Currently, the lead developer of GeoGebra is Michael Borcherds, a secondary maths teacher.

After a successful Kickstarter campaign, GeoGebra expanded their offerings to include an iPad, an Android and a Windows Store app version.

Dynamic geometry, algebra and calculus
GeoGebra is dynamic geometry software. Constructions can be made with points, vectors, segments, lines, polygons, conic sections, inequalities, implicit polynomials and functions. All of them can be changed dynamically afterwards. Elements can be entered and modified directly on screen, or through the Input Bar. GeoGebra has the ability to use variables for numbers, vectors and points, find derivatives and integrals of functions and has a full complement of commands like Root or Extremum. Teachers and students can use GeoGebra to make conjectures and to understand how to prove geometric theorems.

Its main features are:
 * Dynamic Geometry Environment
 * Built-in CAS
 * Allows scripting
 * Built-in spreadsheet with extended skills

Exporting
Constructed projects can be exported in several formats. Dynamic applets can be directly uploaded to GeoGebraTube, exported to html (as a single file suitable for use in a virtual learning environment (VLE), such as Moodle). Possible direct export to HTML5 or Animated GIF. SVG vector images can be further edited using third party software, e.g. Inkscape. EMF vector formats can be directly imported in several Office applications. There are also options for exporting to the system clipboard, PNG, PDF, EPS, PGF/TikZ and Asymptote.

GeoGebra can also create code that can be used inside LaTeX files in order to create that same images that GeoGebra generates, through the PSTricks package, the PGF/TikZ packages, or Asymptote code.

GeoGebraTube is the official repository website of GeoGebra products and GeoGebra related free resources. It started working in June 2011, and it contains about 60 000 (in January 2014) materials, like interactive presentation, games, and lessons made by GeoGebra.

Licensing
Most parts of the GeoGebra program are licensed under GPL, making them free software. However some parts, including the Windows and Mac installers, have a license which forbids commercial use and are therefore not free software. In practice, this means that non-commercial use by teachers and students is always free of charge, while commercial users may need to pay license fees. For details see the GeoGebra license description.

Since July 2010 the Debian GNU/Linux distribution offers a free version of GeoGebra 4.0 in which all unfree parts of the program were removed or replaced by free software. This version may be used for commercial purposes without paying licensing fees. However, starting with version 4.2 since December 2012, the licence is changed to be more restrictive so that GeoGebra cannot be included in Debian GNU/Linux any longer. On the other hand, the software can still be downloaded from its official download page free of charge for many platforms (including Debian as well).

Community
The GeoGebra Institutes (IGI) are more than 120 (in 2013 March) non-profit organizations around the world. GeoGebra Institutes join teachers, students, software developers and researchers to support, develop, translate and organise the Geogebra related tasks and projects. Local GeoGebra Institutes are groups at schools and universities who support students and teachers in their region. As part of the International GeoGebra Institute network they share free educational materials, organize workshops, and work on projects related to GeoGebra. GeoGebra Institute may certify local GeoGebra users, experts, and trainers according Guidelines.

Awards

 * MERLOT Award for Exemplary Online Learning Resources – MERLOT Classics 2013 (Las Vegas, Nevada, USA)
 * NTLC Award 2010: National Technology Leadership Award 2010 (Washington D.C., USA)
 * Tech Award 2009: Laureate in the Education Category (San Jose, California, USA)
 * BETT Award 2009: Finalist in London for British Educational Technology Award
 * SourceForge.net Community Choice Awards 2008: Finalist, Best Project for Educators
 * AECT Distinguished Development Award 2008: Association for Educational Communications and Technology (Orlando, USA)
 * Learnie Award 2006: Austrian Educational Software Award for "Wurfbewegungen mit GeoGebra" (Vienna, Austria)
 * eTwinning Award 2006: 1st prize for "Crop Circles Challenge" with GeoGebra (Linz, Austria)
 * Les Trophées du Libre 2005: International Free Software Award, category Education (Soisson, France)
 * Comenius 2004: German Educational Media Award (Berlin, Germany)
 * Learnie Award 2005: Austrian Educational Software Award for "Spezielle Relativitätstheorie mit GeoGebra" (Vienna, Austria)
 * digita 2004: German Educational Software Award (Cologne, Germany)
 * Learnie Award 2003: Austrian Educational Software Award (Vienna, Austria)
 * EASA 2002: European Academic Software Award (Ronneby, Sweden)