There are a number of tools to graph equations in the App Store, but the “Graphing Calculator” by Gabor Nagy has the dual advantage of being both excellent and free. As a math major myself, and a former user of programs such as “Mathematica”, I was genuinely impressed with the interface and functionality of this tool.

When I first downloaded “Starmap” from French Publisher Star-map, I was somewhat disappointed. The star charts were accurate of course, but panning around was clunky, with a low refresh rate. As the author explains in his FAQ:
“The refresh rate of the sky map is about 3 frames per seconds when you slide it with your finger. (…)

Preschool Adventure is a set of fun, interactive learning activities. Children will learn about colors by revealing a variety of colorful seas creatures, explore the parts of the body deep in the jungle with a funny chimpanzee, discover farm animal sounds out in the barnyard and learn the names of shapes while traveling to a distant alien planet. (…)

Using anatomical illustrations from Netter’s Atlas of Human Anatomy (4th edition), Netter’s Anatomy Flash Cards allows you to carry the bestselling reference for human anatomy on your iPhone or iPod Touch. (…)

A frontend to the popular website, wwwJDic uses a clean iPhone interface to access Jim Breen’s wwwJDIC from anywhere in the world. (…)

Use Mandelbrot from Alpheccar to explore the famous Mandelbrot and Julia sets with a few gestures. Mandelbrot and Julia sets are famous mathematical objects where art meets mathematics.
Zooms are animated. You’ll feel like you are diving inside the Mandelbrot and Julia sets.