On Wed, Jun 2, 2010 at 8:02 PM, Scott <scotta_2...@yahoo.com> wrote: > Aaron > > Thanks for the tips. > > Where are the "issues" located? > > I am numerically evaluating x*cos(x)/sin(x) on [-pi/2,pi/2] and the > spurious singularity at x= 0 is giving me grief. x/sin(x)=1 at x=0. > > After looking at my problem it seems that I should have asked if there > is and efficient way to embed sin(x)/x or x/sin(x) in a function that > is evaluated at 0. I will probably use a 7th order Taylor series > unless there another clever option. > > The series for x/sin(x) has much better convergence than the series > for x*cot(x) in my range of interest (+- pi/2). > > In [41]: (x/sin(x)).series(x, 0, 8) > Out[41]: 1 + x**2/6 + 7*x**4/360 + 31*x**6/15120 + O(x**7) >
SymPy is missing the sinc function. I created an issue: http://code.google.com/p/sympy/issues/detail?id=1952 If you want to have a go at implementing this function (it shouldn't be too hard), see sympy/functions/elementary/trigonometric.py Fredrik -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sy...@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.
