is the 
term in the series, the test consists of calculating:
is: one of several tests for the convergence or divergence of a series. If is the term in the series, the test consists of calculating:
There are three possible outcomes:
implying convergence,
implying divergence,
implying that the test is incapable of providing a definite answer.
[M1.7]
Copyright 1997, The Open University