Difference between revisions of "Leibniz criterion"
From Encyclopedia of Mathematics
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\sum_{n=1}^{\infty}(-1)^{n+1}a_n,\quad a_n>0, | \sum_{n=1}^{\infty}(-1)^{n+1}a_n,\quad a_n>0, | ||
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| − | decrease monotonically ($a_n | + | decrease monotonically ($a_n\geq a_{n+1}$, $n=1,2,\dots$) and tend to zero ( $\lim\limits_{n\to\infty}a_n=0$ ), then the series converges; moreover, a remainder of the series, |
\begin{equation} | \begin{equation} | ||
\sum_{k=n+1}^{\infty}(-1)^{k+1}a_k, | \sum_{k=n+1}^{\infty}(-1)^{k+1}a_k, | ||
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====References==== | ====References==== | ||
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| + | |valign="top"|{{Ref|Kn}}|| K. Knopp, "Theorie und Anwendung der unendlichen Reihen" , Springer (1964) (English translation: Blackie, 1951 & Dover, reprint, 1990) | ||
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Latest revision as of 20:16, 9 December 2013
2020 Mathematics Subject Classification: Primary: 40A05 [MSN][ZBL]
for convergence of an alternating series
If the terms of an alternating series \begin{equation} \sum_{n=1}^{\infty}(-1)^{n+1}a_n,\quad a_n>0, \end{equation} decrease monotonically ($a_n\geq a_{n+1}$, $n=1,2,\dots$) and tend to zero ( $\lim\limits_{n\to\infty}a_n=0$ ), then the series converges; moreover, a remainder of the series, \begin{equation} \sum_{k=n+1}^{\infty}(-1)^{k+1}a_k, \end{equation} has the sign of its first term and is less than it in absolute value. The criterion was established by G. Leibniz in 1682.
Examples
- Leibniz series $\sum\limits_{n=1}^{\infty}\frac{(-1)^{n+1}}{2n-1}$.
References
| [Kn] | K. Knopp, "Theorie und Anwendung der unendlichen Reihen" , Springer (1964) (English translation: Blackie, 1951 & Dover, reprint, 1990) |
How to Cite This Entry:
Leibniz criterion. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Leibniz_criterion&oldid=29175
Leibniz criterion. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Leibniz_criterion&oldid=29175
This article was adapted from an original article by V.I. Bityutskov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article