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MathGroup Archive 2004

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Re: Re : Re: 1) Global Real Space and 2) Histogram Y-axis

  • To: mathgroup at smc.vnet.net
  • Subject: [mg51692] Re: Re : Re: 1) Global Real Space and 2) Histogram Y-axis
  • From: p-valko at tamu.edu (Peter Valko)
  • Date: Fri, 29 Oct 2004 03:39:35 -0400 (EDT)
  • References: <clpqo8$9vo$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Florian,

For your example even that is not enough!
You have to use

expr=Integrate[1/(x^2 + x + 1), x];
Simplify[ComplexExpand[expr, TargetFunctions -> {Re, Im}], Element[x, Reals]]

to get the answer you would like to see: 

(2*ArcTan[(1 + 2*x)/Sqrt[3]])/Sqrt[3]

Peter

"Florian Jaccard" <florian.jaccard at eiaj.ch> wrote in message news:<clpqo8$9vo$1 at smc.vnet.net>...
> Hello  Steve,
> 
> I suggest not to use RealOnly.
> With the package loaded, there are horrible mistakes with 5.0. 
> (Let us call it "bugs")
> 
> For example :
> 
> In[3]:=
> << "Miscellaneous`RealOnly`"
> 
> In[10]:=
> Integrate[1/(x^2 + x + 1), x]
> 
> Out[10]=
> x/(1 + x + x^2)
> 
> Which is wrong, of course !
> 
> So it is better to use 
> ComplexExpand     and 
> Simplify[expr,Element[x,Reals]] 
> and so on!
> 
> Regards
> 
> F.Jaccard
> 
> 
> -----Message d'origine-----
> De : Steve Luttrell [mailto:steve_usenet at _removemefirst_luttrell.org.uk] 
> Envoyé : mercredi, 27. octobre 2004 07:54
> À : mathgroup at smc.vnet.net
> Objet :  Re: 1) Global Real Space and 2) Histogram Y-axis
> 
> Use the Miscellaneous`RealOnly` package.
> 
> Steve Luttrell
> 
> "Skirmantas Janusonis" <skirmantas.janusonis at yale.edu> wrote in message 
> news:clcng4$q2p$1 at smc.vnet.net...
> > I'd like to thank Janos D. Pinter and DrBob for their advice on NMinimize,
> > which I found very helpful.
> >
> > Mathematica is so carefully designed that its accuracy sometimes may be
> > annoying. Namely, it never forgets about complex numbers and sometimes I
> > wish it did. My question is this: is it possible to tell a notebook that 
> > it
> > has to deal only with real numbers? It would be nice to have some global
> > setting so that one doesn't have to specify the same assumptions over and
> > over again.
> >
> > My second question is this: How do I adjust the range of the y-axis of a
> > histogram? PlotRange->{min,max} doesn't seem to work.
> >
> > Thanks!
> >
> > Skirmantas
> >
> >


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