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Re: DSolve bug

  • To: mathgroup at smc.vnet.net
  • Subject: [mg97808] Re: DSolve bug
  • From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
  • Date: Sun, 22 Mar 2009 05:48:18 -0500 (EST)
  • References: <gq2ep1$e8g$1@smc.vnet.net>

Hi Sotirios,

Why do you think it's a bug. C[1][z][x] is a perfectly legitimite way
to type a function of two variables. Look here:

In[64]:= f[x_][y_][z_] := x^y^z

In[65]:= f[a][b][c]

Out[65]= a^b^c

Checking the solution:

In[63]:= D[C[1][z][x] + C[2][z][y], x, y]

Out[63]= 0

No problemo.

Cheers -- Sjoerd

On Mar 21, 12:16 pm, Sotirios Bonanos <sbon... at inp.demokritos.gr>
wrote:
> Hello,
>
> I have encountered the following bug in DSolve:
>
> DSolve[D[F[x, y, z], x, y] == 0, F[x, y, z], {x, y, z}]
>
> gives {{F[x, y, z] -> C[1][z][x] + C[2][z][y]}}
>
> instead of {{F[x, y, z] -> C[1][x, z] + C[2][y, z]}}
>
> I don't know if this has been fixed in Mathematica 7, but it is present i=
n versions 5 and 6.
>
> S. Bonanoshttp://www.inp.demokritos.gr/~sbonano/



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