Namespaces
Variants
Actions

Difference between revisions of "Lobachevskii criterion (for convergence)"

From Encyclopedia of Mathematics
Jump to: navigation, search
(Importing text file)
 
m (TeX encoding is done)
Line 1: Line 1:
A series <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600101.png" /> with positive terms <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600102.png" /> tending monotonically to zero converges or diverges according as the series
+
{{TEX|done}}
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600103.png" /></td> </tr></table>
+
A series $\sum_{n=1}^{\infty}a_n$ with positive terms $a_n$ tending monotonically to zero converges or diverges according as the series
 
+
\begin{equation}
converges or diverges, where <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600104.png" /> is the largest of the indices of the terms <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600105.png" /> that satisfy the inequality <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600106.png" />, <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/l/l060/l060010/l0600107.png" />.
+
\sum_{m=0}^{\infty}\, p_m2^{-m}
 +
\end{equation}
 +
converges or diverges, where $p_m$ is the largest of the indices of the terms $a_n$ that satisfy the inequality $a_n\geq 2^{-m}$, $n=1,\dots,p_m$.
  
 
It was proposed by N.I. Lobachevskii in 1834–1836.
 
It was proposed by N.I. Lobachevskii in 1834–1836.

Revision as of 06:07, 14 December 2012


A series $\sum_{n=1}^{\infty}a_n$ with positive terms $a_n$ tending monotonically to zero converges or diverges according as the series \begin{equation} \sum_{m=0}^{\infty}\, p_m2^{-m} \end{equation} converges or diverges, where $p_m$ is the largest of the indices of the terms $a_n$ that satisfy the inequality $a_n\geq 2^{-m}$, $n=1,\dots,p_m$.

It was proposed by N.I. Lobachevskii in 1834–1836.

How to Cite This Entry:
Lobachevskii criterion (for convergence). Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Lobachevskii_criterion_(for_convergence)&oldid=29181
This article was adapted from an original article by V.I. Bityutskov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article