Your saying that something is not a bug does not mean everyone will agree
with you.
Or even that it will result in non-buggy results. Many "bugs" reported on
sci.math.symbolic
by one writer as bugs in "integrate" in Maple, are bugs in simplification,
sometimes
just like this "obvious" but sometimes wrong feature.
In particular, you may not need reminding about a=0 in this case, but what
about
in other cases, where Maxima just goes ahead without you... e.g.
solve (sin(x-y)/(x-y)=0,x)
returns x=y;
but this is not a solution, which can be seen either by direct substitution
or
taking a limit.
RJF
> -----Original Message-----
> From: Richard Hennessy [mailto:rvh2007 at comcast.net]
> Sent: Wednesday, September 10, 2008 7:26 AM
> To: fateman at EECS.Berkeley.EDU; 'John Pye'; maxima at math.utexas.edu
> Cc: 'Edwin Woollett'
> Subject: Re: [Maxima] integrate returns undefined
>
> This is not a bug, this simplifies to 1
>
> a/a -> 1
>
> with no assumptions made. I have noticed that in general
> radcan(expr1/expr1) simplifies to 1 and Maxima never says
> except when expr1
> = 0. Which I find useful since I know about the possibility
> that expr1
> could be zero but I don't really need to be reminded of this case. I
> definitely would not want to be asked is expr1 = zero all the
> sime when
> cancelling terms. That would be annoying.
>
> Rich
>
>
> ----- Original Message -----
> From: "Richard Fateman" <fateman at cs.berkeley.edu>
> To: "'John Pye'" <john.pye at anu.edu.au>; <maxima at math.utexas.edu>
> Cc: "'Edwin Woollett'" <woollett at charter.net>
> Sent: Tuesday, September 09, 2008 11:56 PM
> Subject: Re: [Maxima] integrate returns undefined
>
>
> > Not so clear a bug.
> > (n-m)/(n-m) simplifies to 1.
> > But if you know n=m, then you have 0/0. So is it a bug if
> (n-m)/(n-m) -->
> > 1?
> >
> > Answer: maybe. But not clear :)
> >
> > RJF
> >
> >
> >> -----Original Message-----
> >> From: maxima-bounces at math.utexas.edu
> >> [mailto:maxima-bounces at math.utexas.edu] On Behalf Of John Pye
> >> Sent: Tuesday, September 09, 2008 6:47 PM
> >> To: maxima at math.utexas.edu
> >> Cc: Edwin Woollett
> >> Subject: Re: [Maxima] integrate returns undefined
> >>
> >> I can confirm that behaviour; it looks like a clear bug to me.
> >>
> >> Cheers
> >> JP
> >>
> >> Edwin Woollett wrote:
> >> > integrate(..) returns undefined when it
> >> > should know the answer.
> >> >
> >> > (%i1) declare( [ m, n ], integer )$
> >> > (%i2) assume ( m > 0, n > 0 )$
> >> > (%i3) integrate( cos(m*x)^2, x, 0, 2*%pi );
> >> > (%o3) %pi
> >> > (%i4) integrate( cos(m*x)*cos(n*x), x, 0, 2*%pi );
> >> > Is n - m positive, negative, or zero?
> >> >
> >> > zero;
> >> > (%o4) undefined
> >> >
> >> > Is this a known bug?
> >>
> >> _______________________________________________
> >> Maxima mailing list
> >> Maxima at math.utexas.edu
> >> http://www.math.utexas.edu/mailman/listinfo/maxima
> >>
> >
> > _______________________________________________
> > Maxima mailing list
> > Maxima at math.utexas.edu
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>
>