It calculates, graphs, and does other things that you are used to. So what's the difference?
The difference is the way this is developed and distributed. You can download it for free! Try it out, see what you like and don't like, and let me know. Bugs will be fixed, features will be implemented, and new versions will be released, all without costing an arm and a leg.
This program is free and always will be. You can download every version that will ever exist.
Email: gregholmes@users.sourceforge.net