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MathGroup Archive 1998

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Re: Re: Way to evaluate D[(1-x^2)y''[x],{x,n

  • To: mathgroup at smc.vnet.net
  • Subject: [mg15004] Re: [mg14961] Re: [mg14914] Way to evaluate D[(1-x^2)y''[x],{x,n
  • From: "Fred Simons" <wsgbfs at win.tue.nl>
  • Date: Sat, 5 Dec 1998 01:30:10 -0500
  • In-reply-to: <366332FB.2869539C@col2.telecom.com.co>
  • Sender: owner-wri-mathgroup at wolfram.com

Jurgen,

Rather in a hurry: Now I understand your question, glad to see that  it
was not really a question.

Your proposal is a real improvement. Obviously there is something in 
Mathematica I do not understand. I had the idea that when Mathematica 
returns the original command, it will try to use other (in this case 
its own) rules. I was inspired by some Mathematica output of the form

Integrate[.....] -> If[ condition, 12, Integrate[.....] ]

where the third argument of If is identical to the command. But it  does
not work in this way, as your example (and a similar one from  one of
my collleagues) shows. I have to think it over.

Many thanks,

Fred

(PS I just noticed that my private reaction to you was on the mailing 
list. I do not understand how that could have happened, anyway I 
apologize.)


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