Apache OpenOffice Math is a free, open-source, full-featured mathematics application for Windows, Mac OS X, and Linux. It is designed to work with the Apache OpenOffice suite of office productivity applications, allowing users to quickly and easily create mathematical equations, formulas, and diagrams. It includes a graphical equation editor, a full-featured spreadsheet, and a 3D grapher. It is an ideal application for students, teachers, and scientists who need to express mathematical concepts in a concise and easy to understand manner. Math also supports the use of mathematical symbols and characters, making it perfect for creating documents for scientific and mathematical research.
Discontinued Discontinued, see notice on http://rlehy.free.fr.
It has more complete options and a larger community.