From: rusin@vesuvius.math.niu.edu (Dave Rusin)
Newsgroups: sci.math.symbolic
Subject: Re: differentiation in maple
Date: 22 Dec 1997 15:37:57 GMT

In article <brcu3c4bqp4.fsf@math.uic.edu>,
Vladimir V. Egorin <vladimir@math.uic.edu> wrote:
>I am trying to implement differentiation in Maple, defined by the
>following rules:
>
>1)  diff(a*b,x) = diff(a,x) + a * diff(b,x)
>2)  diff(1/x,x) = -1/x

Do you really want this? Rule 1 implies that (b-1)*diff(a,x) = (a-1)*diff(b,x)
for all  a  and  b, so that (taking b=1/x) Rule 2 implies
	diff(a,x) = (a-1)(-1/x)/(1/x - 1) = (a-1)/(x-1)
for all  a.

dave