Somebody tweeted last week that The Geometer’s Sketchpad was free for iPads until September 1. I have never been a fan of GSP, preferring to use GeoGebra instead, but I installed it mostly because it was free. I tried it out, and it turns out it is pretty darn good.
You can get the free Sketchpad Explorer on the iTunes App Store. I have no idea what it will cost after September 1, but I’d pay for this app. You can’t create GSP applets with it, but you can view and explore already created ones. The app comes built-in with a series of Algebra, Geometry and Elementary applets. The built-in ones are really nice. A slope one is shown below.
I think the real power, though, is in the Sketch Exchange site, where you can download and transfer applets built for the iPad to your device. It is easy to do this through iTunes once you download the applets from the exchange site. This exchange site will only grow and have more and more available applets over time. Two screenshots are shown below.
Recommendation: Get this app. You can’t beat the price.