Lecture

Convergence of Series

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In course

MATH-101(d): Analysis I

Étudier les concepts fondamentaux d'analyse et le calcul différentiel et intégral des fonctions réelles d'une variable. ...

Description

This lecture covers the convergence of series, including the harmonic series, geometric series, and the criteria for convergence such as the Leibniz criterion. It also explores the comparison test and the D'Alembert criterion, providing examples and demonstrating the convergence and divergence of series.

Official source

Ontological neighbourhood

Mathematics

Analysis: Calculus

Related concepts (32)

Ratio test

In mathematics, the ratio test is a test (or "criterion") for the convergence of a series where each term is a real or complex number and an is nonzero when n is large. The test was first published by Jean le Rond d'Alembert and is sometimes known as d'Alembert's ratio test or as the Cauchy ratio test. The usual form of the test makes use of the limit The ratio test states that: if L < 1 then the series converges absolutely; if L > 1 then the series diverges; if L = 1 or the limit fails to exist, then the test is inconclusive, because there exist both convergent and divergent series that satisfy this case.

Convergence tests

In mathematics, convergence tests are methods of testing for the convergence, conditional convergence, absolute convergence, interval of convergence or divergence of an infinite series . If the limit of the summand is undefined or nonzero, that is , then the series must diverge. In this sense, the partial sums are Cauchy only if this limit exists and is equal to zero. The test is inconclusive if the limit of the summand is zero. This is also known as the nth-term test, test for divergence, or the divergence test.

Direct comparison test

In mathematics, the comparison test, sometimes called the direct comparison test to distinguish it from similar related tests (especially the limit comparison test), provides a way of deducing the convergence or divergence of an infinite series or an improper integral. In both cases, the test works by comparing the given series or integral to one whose convergence properties are known.

Limit comparison test

In mathematics, the limit comparison test (LCT) (in contrast with the related direct comparison test) is a method of testing for the convergence of an infinite series. Suppose that we have two series and with for all . Then if with , then either both series converge or both series diverge. Because we know that for every there is a positive integer such that for all we have that , or equivalently As we can choose to be sufficiently small such that is positive. So and by the direct comparison test, if converges then so does .

Alternating series test

In mathematical analysis, the alternating series test is the method used to show that an alternating series is convergent when its terms (1) decrease in absolute value, and (2) approach zero in the limit. The test was used by Gottfried Leibniz and is sometimes known as Leibniz's test, Leibniz's rule, or the Leibniz criterion. The test is only sufficient, not necessary, so some convergent alternating series may fail the first part of the test. A series of the form where either all an are positive or all an are negative, is called an alternating series.

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Convergence of Series

Explores the convergence of series, including geometric and harmonic series, absolute convergence, and comparison criteria.

Convergence Criteria

Covers convergence criteria for series, including comparison, Cauchy's root test, and d'Alembert's ratio test.

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Related concepts (32)

Ratio test

Convergence tests

Direct comparison test

Limit comparison test

Alternating series test