> > But other sums are simply wrong. > > k = var('k') > sum(x^(2*k)/factorial(2*k),k,0,oo) > > gives > > -1/4*sqrt(2)*sqrt(pi)*x^(3/2) > > but the answer should be sinh(x). > > Hmm. That shouldn't be happening, though I wouldn't be surprised if it didn't turn out as easy as that.
(%i1) load(simplify_sum); (%o1) /Users/.../Sage-5.12-OSX-64bit-10.6.app/Contents/Reso\ urces/sage/local/share/maxima/5.29.1/share/solve_rec/simplify_sum.mac (%i3) display2d:false; (%o3) false (%i4) simplify_sum(sum(x^(2*k)/factorial(2*k),k,0,inf)); (%o4) sqrt(%pi)*bessel_i(-1/2,x)*sqrt(x)/sqrt(2) So I'm not sure why that would happen - maybe because of incorrect Bessel simplification? sage: maxima_calculus('bessel_i(-1/2,x)') bessel_i(-1/2,x) sage: _._sage_() sqrt(2)*sqrt(1/(pi*x))*cosh(x) That gives cosh(x), which I think is what you meant. This is now tracked at http://trac.sagemath.org/ticket/16224. > For other sums, Sage simply repeats what I told it. > > sum(x^(3*k)/factorial(2*k),k,0,oo) > > I understand that Sage has limited exploitation of Maxima's hypergeometric > functionality, and I suspect this is the main issue. Are there any > conceivable workarounds? > > Yeah, that is definitely part of it. See e.g http://trac.sagemath.org/ticket/9908 . - kcrisman -- 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 post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.