For the curious: the Maxima team opened a third bug report: https://sourceforge.net/p/maxima/bugs/4373/ which discusses a possible fix (evaluating conjugate(li[n](x)) does not consider that li[n](x) can also be complex :-( ).
OHappyDay schrieb am Montag, 9. September 2024 um 11:13:18 UTC+2: > The Maxima team has opened two bug reports about this issue: > > incorrect dilogarithm limit in definite integral & incorrect trig > substitution: > > https://sourceforge.net/p/maxima/bugs/4368/ and > https://sourceforge.net/p/maxima/bugs/4369 > > > OHappyDay schrieb am Samstag, 7. September 2024 um 17:20:08 UTC+2: > >> I have reported this to the Maxima team. >> >> wdjo...@gmail.com schrieb am Donnerstag, 5. September 2024 um 15:19:02 >> UTC+2: >> >>> On Thu, Sep 5, 2024 at 9:16 AM 'OHappyDay' via sage-support < >>> sage-s...@googlegroups.com> wrote: >>> >>>> I recently stumbled upon something that looks like a bug: >>>> >>>> Try to integrate the following function: >>>> >>>> f(x)=log(1-4*cos(x)+4) >>>> integrate(f,x,0,pi) >>>> >>>> According to the following video ( >>>> https://www.youtube.com/watch?v=nscSDYApAjM) the result should be >>>> >>>> 2*pi*log(2) >>>> >>>> But my local Sage as well as online I get this result: >>>> >>>> 1/12*I*pi^2 + pi*log(3) - 1/2*pi*log(9/4) + 1/2*I*log(2)^2 - I*dilog(2) >>>> + I*dilog(-1/2) + I*dilog(-2) >>>> >>>> which is a complex number instead. >>>> >>> >>> This could be a bug in Maxima: >>> >>> sage: CC(integrate(f,x,0,pi, algorithm='sympy')) >>> >>> 4.35517218060720 >>> >>> sage: CC(integrate(f,x,0,pi, algorithm='maxima')) >>> >>> 4.44089209850063e-16 - 3.28986813369645*I >>> >>> sage: CC(2*pi*log(2)) >>> 4.35517218060720 >>> >>> >>>> >>>> Similarly this function >>>> >>>> g(x)=log(1-cos(x)+1/4) >>>> integrate(g,x,0,pi) >>>> >>>> results in >>>> >>>> 1/12*I*pi^2 - pi*log(3) + 1/2*pi*log(9/4) + 1/2*I*log(2)^2 - I*dilog(2) >>>> + I*dilog(-1/2) + I*dilog(-2) >>>> >>>> although it should be ZERO. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "sage-support" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to sage-support...@googlegroups.com. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/sage-support/d3714f3c-b193-4d32-9d44-8a5a6d8ec5f1n%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/sage-support/d3714f3c-b193-4d32-9d44-8a5a6d8ec5f1n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/0f3f357c-21fe-4a4f-beb8-f02a915230aen%40googlegroups.com.
