Re: Peculiar output from DSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg37015] Re: [mg36994] Peculiar output from DSolve*From*: Selwyn Hollis <selwynh at earthlink.net>*Date*: Sun, 6 Oct 2002 05:33:16 -0400 (EDT)*References*: <d7.1e734c25.2acec78b@aol.com>*Sender*: owner-wri-mathgroup at wolfram.com

I'm only a little embarassed for not having realized what was happening. (Perhaps I should have slept on it.) Surely I'm not alone in thinking this symbolism is highly nonintuitive. But of course, for it to be otherwise would require another protected symbol... --- Selwyn BobHanlon at aol.com wrote: > In a message dated 10/4/2002 5:13:02 AM, selwynh at earthlink.net writes: > > >>In: DSolve[y*D[u[x, y],x] == x*D[u[x, y],y], u[x,y], {x, y}] >> >>Out: {{u[x, y] -> C[1][(1/2)*(x^2 + y^2)]}} >> >>Square brackets are used as grouping symbols in the result!?? :^O >> >>Somebody say it isn't so. >> > > > "It isn't so" > > The square bracket is not delineating a factor it is enclosing the argument > to an arbitrary function named C[1]. While the function is dependent on both > x and y the dependence only occurs in the combination (x^2+y^2). > > > Bob Hanlon >