The accumulation functiona(t) is a function defined in terms of time t expressing the time value of money. It is used in interest theory. The time value of money (TVM) or the present discounted value is one of the basic concepts of finance, developed by Leonardo Fibonacci in 1202. ...
The accumulation function assumes the initial investment to be 1. To obtain value of money where the initial investment is k, simply have
.
The accumulation function has the following two properties:
a(0) = 1.
It is an increasing function, in most cases, because interest are rarely negative.
In mathematics, functions between ordered sets are monotonic (or monotone) if they preserve the given order. ...
Common accumulation functions
The accumulation function for the two common types of interest: