One of the best known Computer Algebra Systems in university environments is Maxima, based on the legendary CAS developed by the MIT at the end of the 60's, Macsyma. One of its main features is that it's free and open source, therefore, a long list of users is constantly working on its optimization.
The main features of Maxima are:
- Manipulation of all kinds of symbolic expressions: factorials, trigonometric functions, limits of expressions, differential calculus, integral calculus, matrix operations, differential equations, Laplace transforms, Taylor series, etc.
- Evaluation of numerical expressions with great precision.
- Graphic representation in 2D and 3D, and saving them in postscript format.
If you need a computational algebra system, download Maxima, an essential tool for mathematicians, physicists and university students.