Re: transforming exponential of sums into product of exponentials

*To*: mathgroup at smc.vnet.net*Subject*: [mg48668] Re: [mg48654] transforming exponential of sums into product of exponentials*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Thu, 10 Jun 2004 02:43:01 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

It doesn't refuse to do the transformation, it just immediately undoes the transformation. Just write the product and you will see that it simplifies the expression. Exp[a]Exp[b] E^(a + b) You could use Hold Exp[x+y]/.Exp[a_+b_]\[Rule]Hold[Exp[a]Exp[b]] Hold[E^x*E^y] %//ReleaseHold E^(x + y) Bob Hanlon > > From: "Karim Mehadhebi" <Karim.Mehadhebi at wanadoo.fr> To: mathgroup at smc.vnet.net > Date: 2004/06/09 Wed AM 04:17:34 EDT > To: mathgroup at smc.vnet.net > Subject: [mg48668] [mg48654] transforming exponential of sums into product of exponentials > > Dear All, > > I can not understand why Mathmatica refuses to apply rules which transform > exponenials of sums into product of exponentails. > > For instance, > f[x+y] /. f[a_ + b_]-> f[a] f[b] returns f[x] f[y], > whereas > Exp[x+y] /. Exp[a_+b_]->Exp[a]Exp[b] still returns Exp[x+y] > > Any help greatly appreciated > > > > > > Bob Hanlon Chantilly, VA