Here’s a link to the Geogebra website just in case you haven’t yet downloaded it yet. Download the webstart version if you have Java installed on your computer. If not Download the program using the other link Download geogebra link.
Geogebra: http://www.geogebra.org/cms/index.php?option=com_content&task=blogcategory&id=71&Itemid=55
Just downloaded geogebra and it works ok!!!
Great. I hope it helps you with some of the questions. Remember though, you have to do sketches by hand in exams!