The TI-Nspire (CAS) Software includes the same utilities and abilities of the next-gen calculator of the same name. It features a dynamic Computer Algebra System which allows one to manipulate symbolic expressions. While weaker than other commercial mathematics packages such as Mathematica or Matlab, it is a great companion to the calculator.
There are two available editions of this software: the original one and the CAS version. In the CAS version you can find some extra functionality like symbolic calculation.