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Bug in LaguerreL Limit ?

I have found a bug in Limit. I have Mathematica 10.0.1.0 on Windows 8.1.

enter image description here

Limit[(n!*
      LaguerreL[
        n, -1]/(n^(n + 1/4)/Sqrt[2]/E^(n - 2 Sqrt[n] + 1/2)) - 
     1) Sqrt[n], n -> 1000] // N 

Output: 0.649562

Limit[(n!*
      LaguerreL[
        n, -1]/(n^(n + 1/4)/Sqrt[2]/E^(n - 2 Sqrt[n] + 1/2)) - 
     1) Sqrt[n], n -> Infinity]

Output:13/16 = 0.8125

POSTED BY: Mariusz Iwaniuk
7 Replies

Yes, all clear now. In future please remember to cite appropriately (that's a general rule) and to mention when an issue is posted elsewhere (that can save readers time).

The bug, by the way, involves a subtle issue in Series code.

POSTED BY: Daniel Lichtblau

I wanted to help him and other users.

Vaclav Kotesovec wrote:

I already reported this bug in 2012, but still was not fixed (in versions 7,8,9,10) http://code.google.com/p/mathematica/issues/list see Issue 46.

Dr. Wolfgang Hintze wrote:

I see the question: why didn't Wolfram solve the bug? Also it might be interesting information fo other users (like myself).

and now all clear.

POSTED BY: Mariusz Iwaniuk

When you say "I have found a bug in Limit" do you mean you found it on another forum? If so, that should be mentioned explicitly, so as to avoid any appearance of claiming credit for another's work.

POSTED BY: Daniel Lichtblau

Thank you - this is a known issue and our teams are looking into it.

POSTED BY: Moderation Team

Yes, I get the same conflicting answers.

POSTED BY: Kay Herbert

Hi,

can confirm that on version 10.1 on OS X 10.10.3. Wolfram|Alpha gives the same as Limit-> Infinity in the front end:

enter image description here

Cheers,

Marco

POSTED BY: Marco Thiel

enter image description here

POSTED BY: Simon Cadrin
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