Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

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


  • Prev by Date: Extracting Interpolating Function via mathlink
  • Next by Date: Re: how do I display "Power[z,-1]" in an exponetial form?
  • Previous by thread: Re: Forcing a Derivative
  • Next by thread: Re: Re: Re: Forcing a Derivative