Re: Re: Need a better Integrate
- To: mathgroup at smc.vnet.net
- Subject: [mg43052] Re: [mg43019] Re: [mg42976] Need a better Integrate
- From: Andrzej Kozlowski <andrzej at platon.c.u-tokyo.ac.jp>
- Date: Sat, 9 Aug 2003 02:57:53 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On Saturday, August 9, 2003, at 01:32 AM, Dr Bob wrote: >>> This is of course not true. > > It may not be true, but it's not "of course" untrue, unless > > (a) there's an obvious reason it's not true or > (b) you've made some slight attempt, at least, to explain why your > method should work and when. (Or would that spoil your fun?) > > > Congratulations on finding an example that isn't of the form D[g, x] > g^n, but don't strain a muscle patting yourself on the back. > > Bobby I did not find this example. It's just mathematics. Discriminant[f]==0 if an only if f has a multiple (repeated) root. So the method will work not just for powers of polynomials but also for products of powers. One can look up the discriminant in various places (suchas the famous book by Van Der Vaerden on Algebra) or on Eric Eric Weisstein's MathWorld. Daniel Lichtblau told me that that is where he took his implementation from. Andrzej