proof of Leibniz’s theorem (using Dirichlet’s convergence test)
Proof.
Let us define the sequence αn=(-1)n for
n∈ℕ={0,1,2,…}. Then
n∑i=0αi={1for evenn,0for oddn, |
so the sequence ∑ni=0αi is bounded.
By assumption {an}∞n=1 is a bounded decreasing
sequence with limit 0.
For n∈ℕ we set bn:=.
Using Dirichlet’s convergence test, it follows that the series
converges
. Since
the claim follows.
Title | proof of Leibniz’s theorem (using Dirichlet’s convergence test) |
---|---|
Canonical name | ProofOfLeibnizsTheoremusingDirichletsConvergenceTest |
Date of creation | 2013-03-22 13:22:17 |
Last modified on | 2013-03-22 13:22:17 |
Owner | mathcam (2727) |
Last modified by | mathcam (2727) |
Numerical id | 7 |
Author | mathcam (2727) |
Entry type | Proof |
Classification | msc 40A05 |
Related topic | AlternatingSeries |