In this section we will study the use of recurrence relations to define
functions. Along the way we'll learn two new aspects of Mathematica: RSolve [ ]
for solving recurrence relations and ``abstracting'' an
expression into a function.
We'll begin by studying these two new facets of Mathematica, and then we'll apply
them to the problem of computing time payments for loans.
You'll be experimenting with the ideas in this section further in the homework
for this lesson. If you are currently paying off a loan, it might be amusing
(and enlightening) to do some experimenting of your own right now!