Re: ridiculous results with DSolve

• To: mathgroup at smc.vnet.net
• Subject: [mg33374] Re: [mg33363] ridiculous results with DSolve
• From: Andrzej Kozlowski <andrzej at lineone.net>
• Date: Mon, 18 Mar 2002 00:18:53 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```I get:

In[1]:=
DSolve[D[u[x,y],x,x]==0,u,{x,y}]

Out[1]=
{{u->Function[{x,y},C[1][y]+x C[2][y]]}}

In[2]:=
DSolve[D[u[x,y],y,y]==0,u,{x,y}]

Out[2]=
{{u->Function[{x,y},C[1][x]+y C[2][x]]}}

What is supposed to be "ridiculous" here?

Andrzej Kozlowski

Toyama International University
JAPAN
http://platon.c.u-tokyo.ac.jp/andrzej/

On Sunday, March 17, 2002, at 10:33  AM, Diego Catalano Ferraioli wrote:

>
> Hi all !
> Actually I'm interested in implementation of algoritms based on the Lie
> theory of differential equations.
> I was searching for a suitable language for an efficient implementation
> of these algoritms when I discovered that (for example):
>  if you try to solve with Mathematica the trivial PDE
>
>
> D[u[x,y],x,x]==0
>
>    then a Dump occurs, but if you try to solve the equivalent equation
>
>
> D[u[x,y],y,y]==0
>
>   then Mathematica gives the wrong solution
>
>                                                       u[x,y]=
> C[1][x]+C[2][y] .
>
> This result is ridiculous !!!!
> How it is possible?
>
>
>
>                   Diego
>
>
>
>

```

• Prev by Date: Re: ListConvolve Problem?
• Next by Date: Re: ridiculous results with DSolve
• Previous by thread: ridiculous results with DSolve
• Next by thread: Re: ridiculous results with DSolve