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, copy to clipboard as bitmap or enhanced metafile in black-and-white or color, or export to JPEG/PNG file.

- 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.