On Thu, Sep 5, 2024 at 9:16 AM 'OHappyDay' via sage-support < sage-support@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+unsubscr...@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/CAEQuuAUwgTBqvwyANC_gw0xnDZ7JdX%2BKjp95KpxCuPoK4diC2Q%40mail.gmail.com.