Re: Problem with transformation rule of a function -- Another one

*To*: mathgroup at smc.vnet.net*Subject*: [mg53509] Re: [mg53467] Problem with transformation rule of a function -- Another one*From*: Alain Cochard <alain at geophysik.uni-muenchen.de>*Date*: Sat, 15 Jan 2005 01:44:08 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Thank you so much to those who answered. Now, here is another one. The following works as I expect: In[1]:= expr=Integrate[D[g[x,t],t],{x,0,1}] (0,1) Out[1]= Integrate[g [x, t], {x, 0, 1}] In[2]:= g[x_,t_]:= x f[t] In[3]:= expr f'[t] Out[3]= ----- 2 Now I would like to use a transformation rule instead, like in: In[1]:= expr=Integrate[D[g[x,t],t],{x,0,1}] ; In[2]:= expr/. g[x,t]->x f[t] (0,1) Out[2]= Integrate[g [x, t], {x, 0, 1}] I tried various alternatives (with "//", ":>", "Evaluate", using "_" or not, with "Hold/ReleaseHold" -- although not in a fully systematic way, I admit) without success. Is it feasible? Thanks, Alain

**Follow-Ups**:**Re: Re: Problem with transformation rule of a function -- Another one***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**Re: Re: Problem with transformation rule of a function -- Another one***From:*DrBob <drbob@bigfoot.com>