Services & Resources / Wolfram Forums
MathGroup Archive
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1999

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

Search the Archive

Re: Manipulating differential equations

  • To: mathgroup at
  • Subject: [mg18593] Re: [mg18552] Manipulating differential equations
  • From: BobHanlon at
  • Date: Tue, 13 Jul 1999 01:01:26 -0400
  • Sender: owner-wri-mathgroup at


dg1 = c''[x] + g c'[x];

dg1 /. NestList[D[#, x] &, c[x] -> Exp[-a*x], 2] // Simplify

(a*(a - g))/E^(a*x)

Bob Hanlon

In a message dated 7/10/99 7:16:39 AM, martin.heimann at writes:

>I would like to insert test functions into an expression that contains
>dg1 = c''[x] + g c'[x]
>I would like e.g. to replace c[x] by Exp[-a x]:
>dg1/.c[x]->Exp[-a x]
>but this doesn't work; one has to put substitution rules for each of the
>derivatives explicitly. Is there a more elegant way to achieve this?

  • Prev by Date: Re: Not Plotting Vertical Assymptotes
  • Next by Date: Re: Character encoding with Display[]
  • Previous by thread: Re: Manipulating differential equations
  • Next by thread: RE: Manipulating differential equations