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Re: Grad in VectorAnalysis`

• To: mathgroup at smc.vnet.net
• Subject: [mg103846] Re: [mg103822] Grad in VectorAnalysis`
• From: David Bevan <david.bevan at pb.com>
• Date: Fri, 9 Oct 2009 07:15:39 -0400 (EDT)
• References: <200910081149.HAA13507@smc.vnet.net>

It looks to me like you haven't defined f[x, y, z].

I think you'll need

   f[x_, y_, z_] := ...

You might also want to read up on "=" versus ":=".

David %^>


> -----Original Message-----
> From: Murray Eisenberg [mailto:murray at math.umass.edu]
> Sent: 8 October 2009 12:50
> To: mathgroup at smc.vnet.net
> Subject: [mg103822] Grad in VectorAnalysis`
>
> After...
>
>    Needs["VectorAnalysis`"]
>    SetCoordinates[Cartesian[x, y, z]]
>
>    f[x_, y_] = x/(1 - x^2 - y^2)
>
> ... why does the following not actually return the formula for gradient..=

• References:
  • Grad in VectorAnalysis`
    • From: Murray Eisenberg <murray@math.umass.edu>