Re: a problem with differentiation

• To: mathgroup at smc.vnet.net
• Subject: [mg29707] Re: a problem with differentiation
• From: "Orestis Vantzos" <atelesforos at hotmail.com>
• Date: Wed, 4 Jul 2001 03:08:31 -0400 (EDT)
• Organization: National Technical University of Athens, Greece
• References: <9hs0sk\$br6\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Define h=2t^2 but v:=4/2(h^3+4h^2)
The SetDelayed in the definition of v should not disturb your code.
It does allows this though:

In[55]:=
Block[{h = H}, Function[{H}, D[v, h] // Evaluate]]
Out[55]:=
Function[{H}, 2(8 H + 3 H^2)]

The result is a pure Function, which eliminates the problem of h
spontaneously evaluating into 2t^2.
Orestis

"Soh Pek Hooi" <fbasohph at nus.edu.sg> wrote in message
news:9hs0sk\$br6\$1 at smc.vnet.net...
> Hi,
>
> If I have
> h= 2t^2
> v = 4/2(h^3+4h^2)
>
> How do I evaluate D[v,h] in terms of h without having h to be substituted
in
> the following manner?
>
> Function[{h,v}, D[v, h]][2t^2, 4/2(h^3+4h^2)]
>