Logo
Pattern

Discover published sets by community

Explore tens of thousands of sets crafted by our community.

Sequences and Series - Convergence Tests

33

Flashcards

0/33

Still learning
StarStarStarStar

Geometric series test

StarStarStarStar

Converges if the absolute value of the common ratio ∣r∣<1|r| < 1; diverges otherwise.

StarStarStarStar

P-series test

StarStarStarStar

Converges if p>1p > 1; diverges for p≤1p \leq 1.

StarStarStarStar

D'Alembert's ratio test for convergence

StarStarStarStar

Equivalent to the ratio test; converges if lim⁡n→∞∣an+1∣∣an∣<1\lim_{{n \to \infty}} \frac{|a_{n+1}|}{|a_n|} < 1; otherwise, diverges or is inconclusive.

StarStarStarStar

Cauchy's root test for convergence

StarStarStarStar

Equivalent to the root test; converges if lim⁡n→∞∣an∣1n<1\lim_{{n \to \infty}} |a_n|^\frac{1}{n} < 1; otherwise, diverges or is inconclusive.

StarStarStarStar

Cauchy convergence criterion

StarStarStarStar

A sequence converges if for all ϵ>0\epsilon > 0, there exists an NN such that for all m,n≥Nm, n \geq N, ∣am−an∣<ϵ|a_m - a_n| < \epsilon.

StarStarStarStar

Leibniz's test for alternating series

StarStarStarStar

Identical to the alternating series test; converges if the absolute value of the terms decreases monotonically to 00.

StarStarStarStar

Raabe's test

StarStarStarStar

Converges if lim⁡n→∞n(anan+1−1)>1\lim_{{n \to \infty}} n\left(\frac{a_n}{a_{n+1}} - 1\right) > 1; diverges if it is <1< 1; inconclusive if it equals 11.

StarStarStarStar

Gauss's test

StarStarStarStar

Converges if there is a positive number MM and p>1p > 1 such that lim⁡n→∞np(anan+1−1)>M\lim_{{n \to \infty}} n^p\left(\frac{a_n}{a_{n+1}} - 1\right) > M; otherwise, diverges.

StarStarStarStar

Bertrand's test

StarStarStarStar

Converges if lim⁡n→∞n(log⁡(n)(anan+1−1)−1)>0\lim_{{n \to \infty}} n(\log(n)\left(\frac{a_n}{a_{n+1}} - 1\right) - 1) > 0; otherwise, diverges.

StarStarStarStar

Kummer's test

StarStarStarStar

Converges if there is a positive sequence cnc_n such that lim⁡n→∞cn(anan+1−1)>1\lim_{{n \to \infty}} c_n(\frac{a_n}{a_{n+1}} - 1) > 1; otherwise, diverges.

StarStarStarStar

Dirichlet's test

StarStarStarStar

Converges if ana_n is a monotonic decreasing sequence that tends to 00 and bnb_n is bounded, with partial sums also bounded.

StarStarStarStar

Abel's test

StarStarStarStar

Converges if ana_n is a monotonic convergent sequence and bnb_n is a bounded sequence.

StarStarStarStar

Ratio test

StarStarStarStar

Converges absolutely if lim⁡n→∞∣an+1an∣<1\lim_{{n \to \infty}} \left| \frac{a_{n+1}}{a_n} \right| < 1; diverges if the limit is >1> 1 or infinity; test is inconclusive if the limit equals 11.

StarStarStarStar

Gauss's test for convergence

StarStarStarStar

Similar to Gauss's test but modified specifically for hypergeometric series; involves complex analysis for determination.

StarStarStarStar

Frobenius method

StarStarStarStar

Used primarily for power series solutions to differential equations; convergence depends on the radius of convergence around singular points.

StarStarStarStar

Euler's convergence test

StarStarStarStar

Converges when the product of nn times the difference between consecutive terms ana_n and an+1a_{n+1} is convergent.

StarStarStarStar

Gregory's test

StarStarStarStar

A particular form of the alternating series test, where convergence is determined if the alternating sum of the sequence's terms tends to a limit.

StarStarStarStar

Lambert's test

StarStarStarStar

Converges if nan→0na_n \rightarrow 0 as n→∞n \rightarrow \infty for an>0a_n > 0 and an≥an+1a_n \geq a_{n+1} for all nn.

StarStarStarStar

Stirling's test

StarStarStarStar

Converges if there is a constant C>0C > 0 such that anan+1=1+Cn+O(1n2)\frac{a_n}{a_{n+1}} = 1 + \frac{C}{n} + O(\frac{1}{n^2}).

StarStarStarStar

Tauber's test

StarStarStarStar

Converges if nanna_n is bounded and ana_n tends to 00 as nn tends to infinity.

StarStarStarStar

Borel's criterion

StarStarStarStar

A series converges if for all ϵ>0\epsilon > 0, there exist only finitely many natural numbers nn such that nan>ϵna_n > \epsilon.

StarStarStarStar

Logarithmic test

StarStarStarStar

Converges if lim⁡n→∞log⁡∣an∣log⁡n>1\lim_{{n \to \infty}} \frac{\log |a_n|}{\log n} > 1; otherwise, diverges.

StarStarStarStar

Riemann series theorem

StarStarStarStar

Any conditionally convergent series can be rearranged to converge to any number or even diverge.

StarStarStarStar

Root test

StarStarStarStar

Converges absolutely if lim⁡n→∞∣an∣n<1\lim_{{n\to\infty}} \sqrt[n]{|a_n|} < 1; diverges if the limit is >1> 1 or infinity; test is inconclusive if the limit equals 11.

StarStarStarStar

Hadamard's formula

StarStarStarStar

Used to find the radius of convergence RR of a power series; R=1lim sup⁡n→∞∣an∣nR = \frac{1}{\limsup_{n \to \infty} \sqrt[n]{|a_n|}}.

StarStarStarStar

Silverman's game

StarStarStarStar

Illustrates a series's convergence via a game with prescribed moves leading to an ever-decreasing remainder; not a formal test.

StarStarStarStar

The area convergence test

StarStarStarStar

For an alternating series where terms are represented by the areas of successive vertical rectangles under a decreasing function, the series converges.

StarStarStarStar

Integral test

StarStarStarStar

If f(n)=anf(n) = a_n, the series converges if ∫1∞f(x)dx\int_{1}^{\infty} f(x) dx converges; diverges otherwise.

StarStarStarStar

Comparison test

StarStarStarStar

If 0≤an≤bn0 \leq a_n \leq b_n and ∑bn\sum b_n converges, then ∑an\sum a_n also converges; if ∑an\sum a_n diverges, then ∑bn\sum b_n also diverges.

StarStarStarStar

Limit comparison test

StarStarStarStar

If lim⁡n→∞anbn=c\lim_{{n \to \infty}} \frac{a_n}{b_n} = c where cc is a positive finite number and ∑bn\sum b_n converges, then ∑an\sum a_n also converges; if ∑bn\sum b_n diverges, then ∑an\sum a_n diverges.

StarStarStarStar

Alternating series test

StarStarStarStar

Converges if the sequence ana_n is decreasing and lim⁡n→∞an=0\lim_{{n \to \infty}} a_n = 0.

StarStarStarStar

Absolute convergence test

StarStarStarStar

A series converges absolutely if the sum of the absolute values of its terms converges.

StarStarStarStar

Conditional convergence test

StarStarStarStar

A series is conditionally convergent if it converges but does not converge absolutely.

Know
0
Still learning
Click to flip
Know
0
Logo

© Hypatia.Tech. 2024 All rights reserved.