Re: Re: Forcing a Derivative
- To: mathgroup at smc.vnet.net
- Subject: [mg50793] Re: [mg50778] Re: Forcing a Derivative
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Tue, 21 Sep 2004 03:49:18 -0400 (EDT)
- Organization: Mathematics & Statistics, Univ. of Mass./Amherst
- References: <cijej8$hlp$1@smc.vnet.net> <200409200139.VAA27554@smc.vnet.net>
- Reply-to: murray at math.umass.edu
- Sender: owner-wri-mathgroup at wolfram.com
Your answer, and those of others, just reinforces my complaint about this limitation of Mathematica today. Why should one have to introduce what is, from a modern mathematical point of view, an extraneous extra variable, "x"? A function f is an object; an "expression in x" such as f[x] is quite another. Or at least it should be! Klaus G wrote: >>... >>Derivative[2][f * g] >>just puts a couple of primes on the product rather than actually computing the dervative. >>Thanks for any insight. >>Cheers, Scott > > > Hi, > > f is NOT f[x], so please try: > > deriv = D[f[x]*g[x], {x, 2}] > Collect[deriv, x] > > regards > Klaus G. > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305
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- From: Karl_boehme_9@msn.com (Klaus G)
- Re: Forcing a Derivative