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Problem with Patterns and Integrate

• To: mathgroup at smc.vnet.net
• Subject: [mg123234] Problem with Patterns and Integrate
• From: Jack McInerney <ejmcinerney at gmail.com>
• Date: Mon, 28 Nov 2011 05:53:30 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com

There is something about using patterns that I don't understand, and
am hoping someone can shed some light.  Here is an example of my
problem.  Say I have a function f[x] and I take the derivative of it.
I can then integrate it and get f[x] back:


In[167]:= expr = D[ f[x], x ]
Out[167]= f=E2=80=B2[x]

In[168]:= Integrate[expr, x]
Out[168]= f[x]

If I use a ReplaceAll and a pattern to do the integration, the
Integrate function treats f'[x] as a constant and returns the wrong
answer:

In[169]:= expr /. func_ ->  Integrate[func,x]
Out[169]= x f=E2=80=B2[x]

Any thoughts as to what I am doing wrong?

Jack

• Follow-Ups:
  • Re: Problem with Patterns and Integrate
    • From: Barrie Stokes <Barrie.Stokes@newcastle.edu.au>
  • Re: Problem with Patterns and Integrate
    • From: Bob Hanlon <hanlonr357@gmail.com>