This is a known bug, https://github.com/sympy/sympy/issues/8404
A._sage_() works because exp_polar(I*pi) is -1 in sage and is unevaluated in SymPy. Isuru Fernando On Fri, Dec 2, 2016 at 2:55 PM, Sébastien Labbé <sla...@gmail.com> wrote: > Can SymPy tell me that A = 1/64*pi**2 by simplifying the polylog in below > example? > > >>> from sympy.abc import n > >>> from sympy import summation, oo > >>> A = summation(1/((2*n+1)^2-4)^2, (n, 0, oo)) > >>> A > -polylog(2, exp_polar(I*pi))/16 + pi**2/96 > >>> A.simplify() > -polylog(2, exp_polar(I*pi))/16 + pi**2/96 > > because it seems doable: > > sage: from sympy.abc import n > sage: from sympy import summation, oo > sage: A = summation(1/((2*n+1)^2-4)^2, (n, 0, oo)) > sage: A._sage_() > 1/64*pi^2 > > This came up in https://ask.sagemath.org/question/35839/sage- > incorrectly-evaluates-series/ > > Sébastien > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sympy+unsubscr...@googlegroups.com. > To post to this group, send email to sympy@googlegroups.com. > Visit this group at https://groups.google.com/group/sympy. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/sympy/1f93f41c-ebf8-4402-990d-cc4f9ca22aa5%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/1f93f41c-ebf8-4402-990d-cc4f9ca22aa5%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CA%2B01voNq9mzBn5MAK-y6C5Ko4dcwfJ7diMN05tsHgAH5rm%3DYCg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
