Mathematica is a computer program performing symbolic mathematical manipulations. Mathematica can factor polynomials, differentiate, integrate, and much more. It can also perform numerical calculations (in arbitrary precision), plot, and work as a word processor (Mathematica's Manual is written in Mathematica). Mathematica runs on a wide range of platforms. The recommended way is to use UD's mainframes. To run Mathematica this way you will need a computer account on the mainframes (and preferably also on DPA computers) and learn a little of Unix operating system. In this setup, the Mathematica program executes instructions on the mainframe. To start it, issue commands, and see Mathematica's outputs, you will have to sit at a terminal. In most cases the terminal will be another computer, under Unix or MS Windows, which can run communication software called X-Windows and in this way access Mathematica executing on the mainframe.
Another option is to have Mathematica installed on your own PC or some PC in DPA that you can use. All UD users can get a free copy of Mathematica for MS Windows. However, to run it, one has to be connected to UD mainframes all the time. Thus, this method makes sense only if one connects over a slow network. Students can also purchase a relatively inexpensive student version of Mathematica, which runs without any restrictions.