#14591: cosh integral incorrect because of abs_integrate
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Reporter: kcrisman | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-5.10
Component: calculus | Keywords:
Work issues: | Report Upstream: N/A
Reviewers: | Authors:
Merged in: | Dependencies:
Stopgaps: |
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See [http://ask.sagemath.org/question/2577/integrate-with-elliptic-
integral-special-function?answer=3545#3545 this ask.sagemath question].
{{{
sage: a = integrate(sqrt(1-1/4*cosh(x)^2),x)
sage: a.full_simplify()
cosh(x)
}}}
Not that I'm an expert here, but at any rate, viewed as real functions
this makes no sense, though perhaps on some branch it does. This happens
because
{{{
Maxima 5.29.1 http://maxima.sourceforge.net
using Lisp ECL 12.12.1
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) domain:complex;
(%o1) complex
(%i2) display2d:false;
(%o2) false
(%i3) B:integrate(sqrt(1-cosh(x)^2/4),x);
(%o3) 'integrate(sqrt(1-cosh(x)^2/4),x)
(%i4) trigsimp(B);
(%o4) 'integrate(sqrt(-(cosh(x)^2-4)/4),x)
(%i5) fullratsimp(B);
(%o5) 'integrate(sqrt(-(cosh(x)^2-4)/4),x)
(%i6) load(abs_integrate);
(%o6)
"/Users/.../sage-5.9.rc1/local/share/maxima/5.29.1/share/contrib/integration/abs_integrate.mac"
(%i7) trigsimp(B);
(%o7) cosh(x)
(%i8) fullratsimp(B);
(%o8) cosh(x)
}}}
I'm not sure we want to unload `abs_integrate` but we need to figure
something out here.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14591>
Sage <http://www.sagemath.org>
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