Re: Another damn simplifying problem: ArcTan
- To: mathgroup at smc.vnet.net
- Subject: [mg59935] Re: Another damn simplifying problem: ArcTan
- From: snoofly <snoofly at snoofly.com>
- Date: Fri, 26 Aug 2005 04:53:25 -0400 (EDT)
- References: <dek7hq$a2t$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Mathieu McPhie wrote: > Can someone please explain this to me: (M v4.something) > > In:= Simplify[ArcTan[-x]+ArcTan[x]] > Out= 0 > > In:= Simplify[ArcTan[-x,1]+ArcTan[x,1]] > Out= ArcTan[-x,1]+ArcTan[x,1] > > Note, I want something more complicated than this obviously. Actually > want something like > > Simplify[ArcTan[-x,y]+ArcTan[x,y]] > > but above is the easiest example of this infuriating programs problem. > > Cheers, Mathieu > The doc for ArcTan[x,y] mentions the quadrant is taken into account. Use x=1,y=2 to see the reasoning why it doesn't simplify to 0.