Math 2.0

Sequences, series, summability Definition

Convergent series

Builds on SeriesPartial sumConvergent sequence

Definition

Let ∑an\sum a_n be a series of real numbers with partial sums sN=∑n=0Nans_N = \sum_{n=0}^{N} a_n. The series is convergent if the sequence (sN)(s_N) is a convergent sequence.

Remarks

The series ∑1/2n\sum 1/2^n converges, since its partial sums 2−1/2N2 - 1/2^N tend to 22. The limit of the partial sums is the sum of the series. A series that does not converge is a divergent series. Changing finitely many terms does not change whether a series converges. It can change the sum.

Reading path

To understand this page from the ground up, read these 7 pages in order. The foundations come first.

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Each page uses the pages above it. The colour of the bar on a box shows how strong the evidence is, and the box also gives it as text. The list has the same pages.
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  1. Sequence definition
  2. Real sequence definition
  3. Limit of a sequence definition
  4. Series definition
  5. Convergent sequence definition
  6. Partial sum definition
  7. Convergent series definition

Where this leads

167 pages build on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Convergent_series, Definition
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