Re: Delayed Derivative Operator
- To: mathgroup at smc.vnet.net
- Subject: [mg81816] Re: [mg81762] Delayed Derivative Operator
- From: Curtis Osterhoudt <cfo at lanl.gov>
- Date: Thu, 4 Oct 2007 04:21:37 -0400 (EDT)
- Organization: LANL
- References: <200710030626.CAA28793@smc.vnet.net>
- Reply-to: cfo at lanl.gov
On Wednesday 03 October 2007 00:26:48 ToddSmith wrote: > Hi, > I would like to be able to have an equation > > eq := D[f[x],x]==5; > > And a substitution rule > > rule = f[x]->x^3; > > And perform the substitution > > eq/.rule > > And get back the equation 3x^2==5. But Mathematica sees f'[x] and > doesn't do any substitutions. I tried a delayed assignment for eq but > it didn't work. What can I do? > > -Thanks Maybe eq := Hold[D[f[x], x] == 5]; rule = f[x] -> x^3; In[7]:= ReleaseHold[eq /. rule] Out[7]= 3 x^2 == 5 will do what you want. -- ========================================================== Curtis Osterhoudt cfo at remove_this.lanl.and_this.gov PGP Key ID: 0x4DCA2A10 Please avoid sending me Word or PowerPoint attachments See http://www.gnu.org/philosophy/no-word-attachments.html ==========================================================
- References:
- Delayed Derivative Operator
- From: ToddSmith <elliptic1@gmail.com>
- Delayed Derivative Operator