Unlike stronger convergence tests, the term test cannot prove by itself that a series converges. In particular, the converse to the test is not true; instead all one can say is:
If then may or may not converge. In other words, if the test is inconclusive.
The harmonic series is a classic example of a divergent series whose terms approach zero in the limit as .[3] The more general class of p-series,
exemplifies the possible results of the test:
If p ≤ 0, then the nth-term test identifies the series as divergent.
If 0 < p ≤ 1, then the nth-term test is inconclusive, but the series is divergent by the integral test for convergence.
If 1 < p, then the nth-term test is inconclusive, but the series is convergent by the integral test for convergence.
Assuming that the series converges implies that it passes Cauchy's convergence test: for every there is a number N such that
holds for all n > N and p ≥ 1. Setting p = 1 recovers the claim[5]
Scope
The simplest version of the term test applies to infinite series of real numbers. The above two proofs, by invoking the Cauchy criterion or the linearity of the limit, also work in any other normed vector space[6] or any additively written abelian group.
^For example, Rudin (p.60) states only the contrapositive form and does not name it. Brabenec (p.156) calls it just the nth term test. Stewart (p.709) calls it the Test for Divergence. Spivak (p. 473) calls it the Vanishing Condition.