TI-Nspire App:

The TI-Nspire App for iPad presents all-in-one functionality that provides reliable, comprehensive computational and analytic tools and capabilities. Plot and explore functions, equations and inequalities, animate points on objects and graphs, and use sliders to explain their behavior. Summarize and analyze data using different graphical methods such as histograms, box plots, bar and pie charts. This is great for any math classroom that cannot afford a class set of calculators.

http://education.ti.com/en/us/products/apps/ti-nspire-app-for-ipad/tabs/overview