       Re: Derivative Evaluation

• To: mathgroup at smc.vnet.net
• Subject: [mg6056] [mg6051] Re: [mg6017] Derivative Evaluation
• From: Lou Talman <me at talmanl.mscd.edu>
• Date: Sun, 16 Feb 1997 01:11:58 -0500
• Sender: owner-wri-mathgroup at wolfram.com

```To evaluate the xk derivative of f[x1, x2, x3,...,xn] at
{a1, a2, a3,...,an}, user

Derivative[0, 0, 0,...,1,...,0][f][a1, a2, a3,...,an]

where the "1" appears in position k between the first set of

[]'s and all other entries are 0.

For higher (pure) derivatives, replace the 1 with the order of

the derivative you want.  Mixed derivatives result when more than
one non-zero entry appears inside the first set of []'s.

--Lou Talman

Begin forwarded message:

John Cigana wrote:
>
> Hello,
>
> I have a 7 parameters multivariate function. i.e. y = f(x1..x7).
>
> I am able to correctly find the partial derivative for each parameter.
>
> However, I can't seem to be able to evaluate my derivative at a given
> point. i.e. f'(x1=0.01, x2=0.5, x3=0.02, ... x7=0.05) = Value !
>
> Any insight on the subject ?? Any help appreciated !
>
> Thanks,
>
> JOHN CIGANA,

```

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