A powerful math program combining numerical and symbolic tools

Euler
Free
Offline
http://euler.rene-grothmann.de/

Euler is a powerful interactive numerical laboratory. It quickly evaluates numerical functions, visualizes results, and allows to test and program numerical algorithms. The system can handle real, complex and interval numbers, vectors and matrices, and additionally a long data type for exact computation. Most routines are written in the high level Euler language and can be modified or extended by the user.