Graphmatica

a powerful, easy-to-use, equation plotter with numerical and calculus features:

- Graph Cartesian functions, relations, and inequalities, plus polar, parametric, and ordinary differential equations.
- Up to 999 graphs on screen at once.
- New data plotting and curve-fitting features.
- Numerically solve and graphically display tangent lines and integrals.
- Find critical points, solutions to equations, and intersections between Cartesian functions.
- Print your graphs or copy to clipboard as bitmap or enhanced metafile in black-and-white or color.
- On-line help and demo files make getting up to speed a snap.

In summary, a great tool for students and teachers of anything from high-school algebra through college calculus.