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Re: Grad in VectorAnalysis`

• To: mathgroup at smc.vnet.net
• Subject: [mg103866] Re: [mg103822] Grad in VectorAnalysis`
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Fri, 9 Oct 2009 07:19:37 -0400 (EDT)
• References: <200910081149.HAA13507@smc.vnet.net>
• Reply-to: drmajorbob at yahoo.com

You defined f with two arguments and used it with three.

No workee.

Bobby

On Thu, 08 Oct 2009 06:49:55 -0500, Murray Eisenberg  
<murray at math.umass.edu> wrote:

> 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...
>
>    Grad[f[x, y, z]]  (* or even Grad[Evaluate[f[x,y,z]]]
>
> ... whereas the following does return it:
>
>    Grad[x/(1 - x^2 - y^2)]
>
>
>


-- 
DrMajorBob at yahoo.com

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