Re: expansion of a complex exponential in terms of Bessel functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg82310] Re: expansion of a complex exponential in terms of Bessel functions*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 17 Oct 2007 04:06:18 -0400 (EDT)*References*: <ff1pgh$8rm$1@smc.vnet.net>

Hi, just write down the rule and don't use Sum[] because otherwise Mathematica will simplify back the Sum[] Regards Jens P. S. Ramanujam wrote: > Dear MathForum > > Is there a way to expand a complex exponential function such as exp[i x_ Cos[y_]] > in terms of Bessel functions in Mathematica? For example, > Exp[i a Cos[b]]->Bessel[0,b]+Sum[i^n Bessel[J[n,b](Exp[i n b]+Exp[-i n b])? > > Regards > > P. S. Ramanujam >