Mathomatic is a highly portable, general purpose CAS (Computer Algebra System)
published under the GNU LGPL license.  Mathomatic can:

    * Solve, simplify, and compare algebraic equations,
    * Perform calculus transformations,
    * Help with finite series analysis,
    * Perform complex number and polynomial arithmetic,
    * Generate efficient C or Java code from equations. 

WWW: http://www.mathomatic.com/