Re: problem writing a simple equation--urgent!!!

*To*: mathgroup at smc.vnet.net*Subject*: [mg50360] Re: [mg50359] problem writing a simple equation--urgent!!!*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Mon, 30 Aug 2004 01:34:32 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

x[y_] := y^2; u[y_, z_] := x[y] + 2*x[z] u[2,4] 36 Bob Hanlon > > From: erkenays at yahoo.com (aysegul) To: mathgroup at smc.vnet.net > Date: 2004/08/29 Sun AM 03:54:07 EDT > To: mathgroup at smc.vnet.net > Subject: [mg50360] [mg50359] problem writing a simple equation--urgent!!! > > Hi all, > I have a problem about writing an equation in mathematica. > I am writing the following equation: > u[x_, y_] = x + 2*y > and when I write for example u[2,4] , it gives the result. But the > problem that I have is expressing this equation with parameters. That > is > u[x[1], x[2]] = x[1] + 2*x[2] > but when I ask u[2,4]; > it gives u[2,4] result.It doesn't calculate. > So, how can I write this equation? > Thanks all. > >