Re: Integration bug
- To: mathgroup at smc.vnet.net
- Subject: [mg38495] Re: Integration bug
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 20 Dec 2002 04:25:13 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <atp6v0$909$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
the bug is more funny try
{#, Integrate[Sin[# + x]/(# + x), {x, -Infinity, Infinity}]} & /@
ToExpression /@
Join[Table[FromCharacterCode[i], {i, 65, 90}],
Table[FromCharacterCode[i], {i, 97, 122}]]
and find out that the integration for symbols
E, X,Y,Z, y,z is correct for all other symbols
one get 0
Regards
Jens
Dana DeLouis wrote:
>
> I am new to Mathematica also, but I seem to recall a bug in the use of
> the variable ?d" before also. This was the first thing I thought of.
> Changing ?d" to something like ?z? gives the answer of Pi.
>
> Removeall
>
> All Global` variables Removed!
>
> $Version
>
> 4.2 for Microsoft Windows (June 5, 2002)
>
> Integrate[Sin[z + x]/(z + x), {x, -Infinity, Infinity}]
>
> Pi
>
> Integrate[Sin[d + x]/(d + x), {x, -Infinity, Infinity}]
>
> 0
>
> (Note: Removeall is my own function that removes all global variables
> and is included to show that all variables are cleared.)
>
> Dana DeLouis
> Windows XP
> $VersionNumber -> 4.2
> = = = = = = = = = = = = = = = = =
>
>
> "David W. Cantrell" <DWCantrell at sigmaxi.org> wrote in message
> news:at4cv9$eta$1 at smc.vnet.net...
> > Using version 4.1,
> >
> > Integral[Sin[x+d]/(x+d),{x,-Infinity,Infinity}] yields 0 .
> >
> > This is, of course, incorrect. (Does version 4.2 make this error
> also?)
> >
> > Mathematica does Integral[Sin[x]/x,{x,-Infinity,Infinity}] correctly
> > however, yielding Pi, which should also be the answer for the original
> > integral (regardless of the value of d).
> >
> > Does anyone have an idea why Mathematica gets the original integral
> wrong?
> >
> > David Cantrell
> >
> > --
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