integrate



Hello

The following code is working with maxima 5.6 and gcl on a pentium :

numer:true;
integrate(1/cos(x)^2,x,0,%PI/4);

RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
much more messages....
RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
(D5) 						        1.0


> Hi David,
>
>      Thanks for the suggestion.  Here are the results.
> It evaluates the limit correctly when one takes the limit
> directly as seen below,
>
> **********
> (C1) numer:true
> ;
>
> (D1)                                 TRUE
> (C2) limit(tan(x+%pi/4),x,0,minus);
>
> (D2)                                  1.0
> (C3)
> **********
>
> but when one tries to integrate(1/cos(x)^2,x,0,%PI/4) it
> still chokes on the divide by zero error.  (See below.)
>
> **********
> (C1) numer:true;
>
> (D1)                                 TRUE
> (C2) integrate(1/cos(x)^2,x,0,%PI/4);
>
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 1.570796326794897 by 51819//32989 = 1.570796326048077
>
> RAT replaced 1.570796326048077 by 51464//32763 = 1.570796325122852
>
> RAT replaced -3.05222354485242E-5 by -1//32763 = -3.05222354485242E-5
>
> RAT replaced -1.57079632512285 by -51109//32537 = -1.57079632418477
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced -0.7853981607873 by -25022//31859 = -0.7853981606453
>
> RAT replaced 1.570796324184774 by 50754//32311 = 1.570796323233574
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 0.78539816339745 by 25732//32763 = 0.78539816256143
>
> RAT replaced 6.283185307179586 by 103993//16551 = 6.283185306023805
> Division by 0
>  -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)
> (C3)
> **********
>
> Something may have gone wrong with the original build.  Looks like
> a precision problem.  What processor are you running on?  Mine is
> in the Athlon Thunderbird series.
>
>
> Cheers,
> Lee
>
> David Holmgren wrote:
> > Hi - I got the limit to evaluate by using numer:true !
> >
> >  Dave Holmgren
> >
> > > -----Original Message-----
> > > From: Lee Rottler [SMTP:rottler at emerald]
> > > Sent: Wednesday, January 16, 2002 4:33 PM
> > > To:   michel.gosse@freesbee.fr
> > > Cc:   maxima@www.ma.utexas.edu
> > > Subject:      Re: [Maxima] integrate
> > >
> > > Hello,
> > >
> > > This is what happened when I tried it under maxima5.6 with gcl.
> > >
> > > ***************
> > > (C2) integrate(1/cos(x)^2,x,0,%PI/4);
> > >
> > > Division by 0
> > >  -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)
> > > (C3)
> > > ***************
> > >
> > > On the other hand I built both gcl and maxima from sources on
> > > the old UT site so if someone has a patch for this please let me
> > > know.   Thanks.
> > >
> > > Cheers,
> > > Lee
> > >
> > > Gosse Michel wrote:
> > > > Hello
> > > >
> > > > With maxima 5.6, the following command :
> > > >
> > > > integrate(1/cos(x)^2,x,0,%PI/4);
> > > > give the answer :
> > > > lim(x->0) tan(x+%PI/4)
> > > >
> > > > I would expect that maxima returns the real 1, because it is a
> > > > very classical function to integrate.
> > > >
> > > > Best regards
> > > >
> > > > ****************************
> > > > Michel Gosse
> > > > michel.gosse@ac-poitiers.fr
> > > > michel.gosse@freesbee.fr
> > > > ****************************
> > > > _______________________________________________
> > > > Maxima mailing list
> > > > Maxima@www.math.utexas.edu
> > > > http://www.math.utexas.edu/mailman/listinfo/maxima
> > >
> > > --
> > > * Lee Rottler                                 
> > > rottler@es.ucsc.edu     * * System Administrator/Scientific
> > > Programmer   Office:  (831) 459-5059 * * High Performance
> > > Computing                   FAX:     (831) 459-3074 * * IGPP -
> > > Earth Sciences                                                *
> > > _______________________________________________
> > > Maxima mailing list
> > > Maxima@www.math.utexas.edu
> > > http://www.math.utexas.edu/mailman/listinfo/maxima
> >
> > _______________________________________________
> > Maxima mailing list
> > Maxima@www.math.utexas.edu
> > http://www.math.utexas.edu/mailman/listinfo/maxima

-- 
****************************
Michel Gosse 
michel.gosse@ac-poitiers.fr
michel.gosse@freesbee.fr
****************************