[Octave-bug-tracker] [bug #60705] [octave forge] (symbolic) int (x * sqrt (abs (x)) on [-1, 1] gives wrong result

[Mike Miller]

Update of bug #60705 (project octave):

                Category:         Octave Function => Octave Forge Package   
                  Status:                    None => Confirmed              
                 Release:                   6.2.0 => dev                    
        Operating System:       Microsoft Windows => Any                    
                 Summary: sym int x*sqrt(abs(x)) on [-1,1] gives 4/5, instead
of 0. => [octave forge] (symbolic) int (x * sqrt (abs (x)) on [-1, 1] gives
wrong result

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Follow-up Comment #1:

Confirmed on Debian. This is actually a bug in upstream SymPy, so it needs to
be fixed there for this to be fixed in Octave symbolic.

Here is the equivalent Python that produces the same wrong result:


from sympy import integrate, sqrt
from sympy.abc import x
f = x * sqrt(abs(x))
y = integrate(f, (x, -1, 1))


I believe this case is covered by this upstream bug report:
https://github.com/sympy/sympy/issues/20982

The workaround suggested there works in this case as well (but of course this
workaround is not exposed using the symbolic package):


y = integrate(f, (x, -1, 1), manual=True)


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