[Maxima-bugs] [ maxima-Bugs-1629723 ] bug in limit, asks sign of IND, encountered in integrator

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Bugs item #1629723, was opened at 2007-01-06 22:15
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Category: Lisp Core - Limit
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: bug in limit, asks sign of IND, encountered in integrator

Initial Comment:
quoted from the mailing list:

On 12/11/06, Daniel Lakeland <dla...@st...> wrote:
>integrate(abs(sin(x)/x),x,0,inf) asks the seemingly stupid question:
>Is  ind  positive, negative, or zero?
>
>the user has absolutely no idea what maxima is asking... I'm going to
>assume that it has something to do with a change of variable deep
>within the integrator... but it's completely opaque to me.

This is definitely a bug, and should be reported.  Integrate is
calling limit, and the bug is actually in the limit routine:

    limit( abs(sin(x))/x , x , inf) => asks sign of ind

IND is supposed to be used by Limit as a return value meaning that the
limit set is bounded, e.g. limit(sin(x),x,inf) => ind, but obviously
here it's gotten its wires crossed.

I suggest you write up the limit bug with a note that definite
integration encounters it.



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