From: Dido Sevilla Date: 2009-02-08T01:04:45+09:00 Subject: Re: Integration/Antidifferentiation Program On Fri, Apr 28, 2006 at 1:31 AM, SleepJunkie wrote: > I'd like to write a program to integrate derivatives to save time on > calc homework and get extra credit in the class. I'm not completely sure > where to start. > http://en.wikipedia.org/wiki/Risch_algorithm There's apparently an algorithm out there that can do symbolic integration of any elementary function, and returns either its antiderivative, or that its antiderivative is not expressible in terms of elementary functions. The only problem that it requires at several points to determine whether two expressions are equal, and that, unfortunately, is difficult, and in some cases actually impossible (undecidable) depending on what functions you allow. See http://en.wikipedia.org/wiki/Richardson's_theorem There's also a whole theory built up from this called differential Galois theory, which extends ideas originally developed by Évariste Galois for the solvability of polynomial equations into solving differential equations, which is really what antidifferentiation is all about: http://en.wikipedia.org/wiki/Differential_Galois_theory You're treading in deep water here, brother. Beware. -- 普通じゃないのが当然なら答える私は何ができる? 普通でも普通じゃなくて感じるまま感じることだけをするよ! http://stormwyrm.blogspot.com