Differentiating functions of vectors
- To: mathgroup at smc.vnet.net
- Subject: [mg9424] Differentiating functions of vectors
- From: Loris Bennett <loris at ferro.physik.TU-Berlin.DE>
- Date: Wed, 5 Nov 1997 01:56:40 -0500
- Organization: Technical University of Berlin
- Sender: owner-wri-mathgroup at wolfram.com
--------------E197FA4B98680772E12058D3
Hello,
If I have a function such as
f[ a_ , b_ ] := a . b
how do I differentitate w.r.t a certain component without having to
specify
the components of the vector explicitly? I had hoped something like
fa[ a_ , b_ ] = D[ f [ a . b ] , a[[1]]]
would work, but it doesn't..
All help greatly appreciated.
Loris
================================================================ Loris
Bennett Tel.: (+49) 30 314 23762
loris at ferro.physik.tu-berlin.de
http://wwwitp.physik.TU-Berlin.DE:80/~loris/ TU Berlin, PN7-1,
Hardenbergstr. 36, 10632 Berlin, FRG
--------------E197FA4B98680772E12058D3
<HTML>
Hello,
<P>If I have a function such as
<P> f[ a_ , b_ ] := a . b
<P>how do I differentitate w.r.t a certain component without having to
specify
<BR>the components of the vector explicitly? I had hoped something like
<P> fa[ a_ , b_ ] = D[ f [ a . b ] , a[[1]]]
<P>would work, but it doesn't..
<P>All help greatly appreciated.
<P>Loris
<PRE>================================================================
Loris
Bennett
Tel.: (+49) 30 314 23762
loris at ferro.physik.tu-berlin.de
<A
HREF="http://wwwitp.physik.TU-Berlin.DE:80/~loris/";>http://wwwitp.physik.TU-Berlin.DE:80/~loris/</A>
TU Berlin, PN7-1, Hardenbergstr. 36, 10632 Berlin, FRG</PRE>
</HTML>
--------------E197FA4B98680772E12058D3--