Re: NInegrate Bug
- To: mathgroup at smc.vnet.net
- Subject: [mg116443] Re: NInegrate Bug
- From: Andrew Moylan <amoylan at wolfram.com>
- Date: Wed, 16 Feb 2011 04:31:53 -0500 (EST)
Hi Kurt,
You should not encounter any problem in Mathematica 8. E.g.
In[1]:= NIntegrate[Sin[x^2], {x, -5, -2}]
Out[1]= -0.276859
In[2]:= N[Integrate[Sin[x^2], {x, -5, -2}]]
Out[2]= -0.276859
Andrew Moylan
Wolfram Research
On Feb 15, 2011, at 10:34 PM, Kurt TeKolste wrote:
> 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
>