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Re: Define a function and its derivatives

  • To: mathgroup at smc.vnet.net
  • Subject: [mg43376] Re: Define a function and its derivatives
  • From: Paul Abbott <paul at physics.uwa.edu.au>
  • Date: Wed, 27 Aug 2003 04:05:02 -0400 (EDT)
  • Organization: The University of Western Australia
  • References: <bi7mvh$p1h$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

In article <bi7mvh$p1h$1 at smc.vnet.net>,
 "Martin Manscher" <reversed-email-rehcsnam at kd.utd.tac> wrote:

> I wish to define a function and its derivatives. The function expression is
> complicated, but the derivatives are fairly simple (full cut-and-paste
> notebook expression below). 

But these derivatives are _not_ correct over the same domain as the 
function (you have z Real which includes z == 0)! The DiracDelta's arise 
(correctly here) because you are taking derivatives of a step function.

Cheers,
Paul

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