This has been one of the best graphing programs I've seen so far. The software covers a variety of mathematical fields, especially calculus and differential equations. This can be used both in class and at home for students who want to explore more about Math and Physics.
Technical Remarks:
It takes a little bit of time to get accustomed to this program. However, the interface is friendly, easy to use. Plus, all the questions are answered in detail in the help section.