I get the same behavior on my machine. It seems like a bug to me. Not sure if the bug is in integrate or in simplify, but could you file this in the issues?
Thanks, ~Luke On May 26, 12:16 pm, Neal Becker <ndbeck...@gmail.com> wrote: > Out[80]: (-2*s**2*w**2 + w**4)/(s**4 + w**4) > > In [81]: _.subs(s,2*pi*I*f) > Out[81]: (8*pi**2*f**2*w**2 + w**4)/(w**4 + 16*pi**4*f**4) > > In [82]: simplify(_) > Out[82]: (8*pi**2*f**2*w**2 + w**4)/(w**4 + 16*pi**4*f**4) > > Notice that this integrand should be strictly positive. It also should give a > simple closed form, if I'm not mistaken. > > In [83]: integrate(_,(f,0,oo)) > Out[83]: -(w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)*log(11*(w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)/(120*pi) + (w**(-12))**(3/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) - > (w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - 64*w**14)**(1/2)*log(oo - > 11*(w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - 64*w**14)**(1/2)/(120*pi) - > (w**(-12))**(3/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) - > (w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)*log(11*(w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)/(120*pi) + (w**(-12))**(3/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) - > (w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - 64*w**14)**(1/2)*log(oo - > 11*(w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - 64*w**14)**(1/2)/(120*pi) - > (w**(-12))**(3/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) + > (w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)*log(-11*(w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)/(120*pi) - (w**(-12))**(3/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) + > (w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - 64*w**14)**(1/2)*log(oo + > 11*(w**(-12))**(1/2)*(-48*I*(w**28)**(1/2) - 64*w**14)**(1/2)/(120*pi) + > (w**(-12))**(3/2)*(-48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) + > (w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)*log(-11*(w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(1/2)/(120*pi) - (w**(-12))**(3/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) + > (w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - 64*w**14)**(1/2)*log(oo + > 11*(w**(-12))**(1/2)*(48*I*(w**28)**(1/2) - 64*w**14)**(1/2)/(120*pi) + > (w**(-12))**(3/2)*(48*I*(w**28)**(1/2) - > 64*w**14)**(3/2)/(960*pi*w**2))/(32*pi) > > In [84]: simplify(_) > Out[84]: 0 > > If the integrand was strickly positive, I don't think it should simplify to 0. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
