On Saturday, September 15, 2012 12:53:34 AM UTC-4, Renan Birck Pinheiro wrote: > > The command sum( ((-1)^k*(x^(2*k+1))/factorial(2*k+1)),k,0,oo) should give > sin(x) - it does in Mathematica. But in Sage it gives > > 1/2*sqrt(pi)*sqrt(2)*sqrt(x)*bessel_j(1/2, x) > > which can't be evaluated numerically: > > _(x=3).N() >
Nice catch! Note that Sage has bessel_[tab] giving bessel_I bessel_J bessel_K bessel_Y and not the lowercase version you have. Apparently we are not converting the Maxima bessel J function to a "Sage-native" version. I believe that http://trac.sagemath.org/sage_trac/ticket/4102 would fix this, once completed. Unfortunately, even typing "bessel_J(1/2,x)" yields an error right now. What you could conceivably do (in addition to achrzesz's great answer) if you just needed numeric values is something along the lines of sage: def f(x): ....: return 1/2*sqrt(pi)*sqrt(2)*sqrt(x)*bessel_J(1/2, x) ....: sage: f <function f at 0x117a268c0> sage: f(3) 0.0325040914386879*sqrt(pi)*sqrt(2)*sqrt(3) sage: f(3).n() 0.141120008059867 but of course that is a few extra lines of code and might not fit in your symbolic framework. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support?hl=en.
