Re: Problem with evaluation of Besel Functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg55984] Re: [mg55963] Problem with evaluation of Besel Functions*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Wed, 13 Apr 2005 01:10:08 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

BesselJ[1.5,0] 0. (BesselJ[x,y]/.y->0)/.x->1.5 0. BesselJ[3/2,y] (Sqrt[2/Pi]*(Sin[y]/y - Cos[y]))/Sqrt[y] You need to use a Limit Limit[BesselJ[x,y]/.x->3/2,y->0] 0 Limit[BesselJ[x,y]/.x->Rationalize[1.5],y->0] 0 Bob Hanlon > > From: Ariel sumeruk <ariel.sumeruk at gmail.com> To: mathgroup at smc.vnet.net > Date: 2005/04/12 Tue AM 05:26:14 EDT > To: mathgroup at smc.vnet.net > Subject: [mg55984] [mg55963] Problem with evaluation of Besel Functions > > Hello > I am having a problem evaluating various functions, One example is the following > > BesselJ[1.5, 0] evaluates to 0 but > (BesselJ[xx, yyy] /. xx -> 1.5) /. yyy -> 0 evaluates to complex infinity > > I seem to encounter many of these problems with Bessel and Legendre > functions where I get actual diffrent numerical results depending on > How I set the parameters. > Thanks for anyone who might help > Ariel > >