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MathGroup Archive 2002

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Re: Integrate fails without warning?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg35283] Re: Integrate fails without warning?
  • From: "Raf" <r_a_f at yahoo.it>
  • Date: Sat, 6 Jul 2002 05:44:30 -0400 (EDT)
  • References: <ag3ef9$72v$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Juan,
I know it's possible to obtain the right answer in many way, but what
surprise me is that:

1) the result is WRONG; and...
2) no error messages are produced; and...
3) no warning messages are produced.

In mathematica-help i didn't find any notes about the functions that must
not be used in Integrate; so i call this a BUG.

Regards,
Bye,
Raf.

"Juan Fuentes" <jfuentes at ff.oc.uh.cu> ha scritto nel messaggio
news:ag3ef9$72v$1 at smc.vnet.net...
> Raf
> I did the integration in another way and obtaine the correct value
> s[t_] := UnitStep[0.5 - t] - UnitStep[t - 0.5]
> Integrate[s[t], {t, 0, 1}]
> 0.
> Maybe the problem is in the function.
> With best regards
> Juan
>
> On Wed, 3 Jul 2002, Raf wrote:
>
> > This regards not only Calculus`Integration`, but also the built-in
> > Integrate:
> > Defining a square wave...
> > In[1]:= ondQua[t_] := If[OddQ[Floor[2t]], -1, 1]
> > ....Mathematica fails completely in computing its defined integral...
> > In[2]:= Integrate[ondQua[t], {t, 0, 1}]
> > Out[2]= 1
> > ....without any warning or error message !!!
> > How is it possible?
> >
> > With NIntegrate the things goes better, but i believe that a similar
risk
> > with Integrate would have to be documented somewhere; if exists some
notes
> > about this using of Integrate on Mathematica-help, please tell me where.
> >
> > Waiting your answers,
> > Thanks,
> > Raf.
> >
> >
> >
> >
>
>



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