Re: Please explain this weird Integrate result
- To: mathgroup at smc.vnet.net
- Subject: [mg60152] Re: Please explain this weird Integrate result
- From: David Bailey <dave at Remove_Thisdbailey.co.uk>
- Date: Sun, 4 Sep 2005 03:02:22 -0400 (EDT)
- References: <dfbevv$inu$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Jose Reckoner wrote: > Expand[Integrate[(2*x)/(2*x - 1), x]] > > gives > > -1/2 + x + Log[-1 + 2*x]/2 > > But, > > Expand[Integrate[1 + 1/(-1 + 2*x), x]] > > gives > > x + Log[-1 + 2*x]/2 > > even though > > (2*x)/(2*x - 1) == 1 + 1/(-1 + 2*x) > > Where did the extra -1/2 in the first result come from? > Hello, You are doing indefinite integration which always produces a result that has an undetermined constant of integration! In maths classes you always have to write +C, or get a mark deducted. C can stand for any constant - including -1/2. David Bailey http://www.dbaileyconsultancy.co.uk