← Back to catalogue
Research draft

alternating series

vr.tr.alternating-series · XCT.REL

Let an agent explain alternating series by definition, convergence tests, error bounds and examples for learners and practitioners.

Thing Registry Cross-cutting context

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent explain alternating series by definition, convergence tests, error bounds and examples for learners and practitioners.

An infinite series whose terms alternate in sign, such as 1 - 1/2 + 1/3 - 1/4 + ..., which converges to ln 2; by the alternating series (Leibniz) test, such a series converges if the absolute values of its terms decrease monotonically to zero, and the error of a partial sum is at most the first omitted term.

What it is for: Analysis, approximation and numerical computation.

It can be test an alternating series for convergence; bound the error of a partial sum; distinguish absolute and conditional convergence; use alternating series in approximations.

Distinguishing features

Signs alternate

Leibniz test applies

Simple error bound

Can converge conditionally

What it looks like

Not physical; series written with alternating plus and minus signs.

How it is recognised

Factor (-1)^n in terms

Alternating signs

Series with all positive terms are not alternating

Related models

is a kind of - category

numerical series

is tested by - test

alternating series test

includes - example

alternating harmonic series

is studied in - field

mathematical analysis

In practice

Families and kinds

alternating harmonic series

alternating series from Taylor expansions

absolutely convergent alternating series

conditionally convergent alternating series

Standards and regulation

No specific regulation

Failure modes and hazards

Applying the test when terms do not decrease

Rearranging conditionally convergent series

Where this came from

wikidata · CC0 1.0

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Test Convergence.

Conditions matter.

Leibniz

Alternating series test.

Leibniz

Leibniz test.

  1. Do the absolute values of the terms decrease to zero? boundary
  2. Does the series therefore converge? definition

Absolute

Absolute convergence.

Absolute

Absolute convergence.

  1. Does the series converge absolutely or only conditionally? boundary
  2. Which test shows it? definition
Error Approximation.

Error bounds are simple.

Bound

Error bound.

Bound

Error bound.

  1. How large can the error of this partial sum be? measurement
  2. How many terms are needed for a given accuracy? measurement

Sum

Known sums.

Sum

Known sums.

  1. What does this alternating series sum to, such as ln 2 or pi/4? provenance
  2. How is it derived? definition
Pitfalls Common errors.

Care is needed.

Rearrange

Rearrangements.

Rearrange

Rearrangements.

  1. What happens if a conditionally convergent series is rearranged? definition
  2. What does the Riemann rearrangement theorem say? definition

Conditions

Test failure.

Conditions

When the test fails.

  1. What if terms do not decrease monotonically? boundary
  2. Which other tests apply? definition
Learning Teaching.

Examples help.

Examples

Worked examples.

Examples

Worked examples.

  1. Can a worked example of the test be given step by step? action
  2. Which exercises help? action

Computation

Numerics.

Computation

Numerical use.

  1. How are alternating series used to compute values numerically? definition
  2. How can convergence be accelerated? definition

What the second pass must settle

  • Should convergence tests be separate entries?
  • How should worked examples be linked?
  • How should the Riemann rearrangement theorem be linked?