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MathGroup Archive 2011

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NInegrate Bug

  • To: mathgroup at smc.vnet.net
  • Subject: [mg116439] NInegrate Bug
  • From: "Kurt TeKolste" <tekolste at fastmail.net>
  • Date: Tue, 15 Feb 2011 06:34:50 -0500 (EST)
  • References: <201102121019.FAA20109@smc.vnet.net> <ij83f7$o6$1@smc.vnet.net>

Has there been a resolution of the NIntegrate bug?

Apparently NIntegrate produces the negative of the right answer for
integrations that start and end to the left of zero -- some of the time.
 (Cos[x] and Sin[x^2] get the wrong result, Sin[x] is good).

Since it is not clear what criterion Mathematica uses in deciding to
give the wrong answer it is not clear when to use NIntegrate[] and when
to use NIntegrate[*Sign[independent variable]].

And this calls into question any results for analysis that uses
NIntegrate -- not a happy situation.

Kurt TeKolste


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