Re: Partial derviatives in mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg95767] Re: Partial derviatives in mathematica
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Mon, 26 Jan 2009 06:49:45 -0500 (EST)
- Organization: The Open University, Milton Keynes, UK
- References: <glk1na$los$1@smc.vnet.net>
In article <glk1na$los$1 at smc.vnet.net>, xareon at gmail.com wrote:
[snip]
> jacobian[{x_, y_}] = Transpose[{\[PartialD]x F[{x, y}], \[PartialD]y F
> [{x, y}]}];
>
> Mathematica's kernel warns me with this message when i try to insert
> it:
>
> Code:
>
> Syntax::sntxf: "jacobian[{x_, y_}] = Transpose[{" cannot be followed
> by
> "\[PartialD]x F[{x, y}], \[PartialD]y F[{x, y}]}];".
[snip]
On my system (v6.0), I have got the more meaningful message:
"Derivative::novar: ?x cannot be interpreted. A partial derivative \
requires a subscript differentiation variable. >>"
The variable must passed as a *subscript* (shortcut Ctrl+-, control +
dash keys) to the symbol partial d.
In[1]:= F[{x_, y_}] = {f1[{x, y}], f2[{x, y}]};
In[2]:= jacobian[{x_,y_}]=Transpose[{\!\(
\*SubscriptBox[\(?\), \(x\)]\ \(F[{x, y}]\)\),\!\(
\*SubscriptBox[\(?\), \(y\)]\ \(F[{x, y}]\)\)}];
(* jacobian[{x_, y_}] = Transpose[{D[F[{x, y}], x], D[F[{x, y}], y]}]; *)
In[3]:= MatrixForm[jacobian[{x, y}]]
Out[3]//MatrixForm=
({1, 0}) ({0, 1})
f1 [{x, y}] f1 [{x, y}]
({1, 0}) ({0, 1})
f2 [{x, y}] f2 [{x, y}]
Regards,
--Jean-Marc