Fwd: Re: Maxima asks about sign of integration(!) variable
Subject: Fwd: Re: Maxima asks about sign of integration(!) variable
From: Richard Fateman
Date: Wed, 25 Sep 2013 17:08:37 -0700
radcan(expr) changes the expression to provide a real value at x=-2 or =2.0.
RJF
-------- Original Message --------
Subject: Re: [Maxima] Maxima asks about sign of integration(!) variable
Date: Thu, 26 Sep 2013 01:44:03 +0200
From: John Lapeyre <lapeyre.math122a at gmail.com>
To: fateman at berkeley.edu
CC: Richard Fateman <fateman at gmail.com>, Jaime Villate
<villate at fe.up.pt>, David Scherfgen <d.scherfgen at googlemail.com>,
"maxima at math.utexas.edu" <maxima at math.utexas.edu>
On 09/26/2013 01:33 AM, Richard Fateman wrote:
> On 9/25/2013 4:11 PM, Jaime Villate wrote:
>> expr : sqrt(1+(4*x^(1/3)-1/16*x^((-1)/3))^2)$
>
> Mathematica, evaluating expr at -2.0
> gives 2.54465 + 4.32153 i
>
> Maxima gives 5.0892904824535
(%i64) float(realpart(expr)),x=-2,numer;
(%o64) 2.544645241226752
(%i65) float(realpart(expr)),x=-2;
(%o65) 5.0892904824535
(%i66) float(imagpart(expr)),x=-2;
(%o66) 0.0
(%i67) float(imagpart(expr)),x=-2,numer;
(%o67) 4.321534242730678
-- John