Re: Deleting Integrate[] transformation rule
- To: mathgroup at smc.vnet.net
- Subject: [mg87609] Re: Deleting Integrate[] transformation rule
- From: UHAP023 at alpha1.rhbnc.ac.uk
- Date: Mon, 14 Apr 2008 05:44:49 -0400 (EDT)
- References: <ftq5ab$it$1@smc.vnet.net> <ftscv1$b81$1@smc.vnet.net>
Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> wrote: : UHAP023 at alpha1.rhbnc.ac.uk wrote: : > When integrating Mathematica knows the result of D[EllipticF[phi,m, phi]] = : ====================================================================!! : Syntax error: a square bracket is missing. : > 1/Sqrt[1-m*Sin[phi]^2]] and will produce expressions containing : > EllipticF[] in its result when it encounters such a pattern. I want : > to prevent this -- that is Unprotect Integrate[] and make it forget : > this rule so that EllipticF[] will not appear in the result. : No need to do that: just use the correct syntax as in, : In[1]:= D[EllipticF[phi, m], phi] : Out[1]= : 1 : --------------------- : 2 : Sqrt[1 - m Sin[phi] ] My apologies. I typed the above in a rush, hence the syntax errors -- including I notice an extraneous ']' in the derivative expression. However you did not address the question. It must be possible to Unprotect Integrate[] and modify it to remove the transformation rule that it uses to pattern match and convert integrand expressions of the form 1/Sqrt[1-m*Sin[phi]^2] to resultant integral expressions of the form EllipticF[phi,m] -- thus preventing EllipticF[] appearing in any result produced by Integrate[]. It is unclear to me from the Mathematica 4.0 docs I have how to do this. The Hold* family of functions, HoldComplete in particular look relevant?? Can anybody confirm/refute and supply a worked example of this procedure? Thanks Tom. : Regards, : -- Jean-Marc Ps. the email address in the header is just a spam trap. -- Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill, Egham, Surrey, TW20 0EX, England. Email: T.Crane at rhul dot ac dot uk Fax: +44 (0) 1784 472794
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