Re: Problem with finding angles between points in Cartesian plane
- To: mathgroup at smc.vnet.net
- Subject: [mg26092] Re: Problem with finding angles between points in Cartesian plane
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 28 Nov 2000 01:55:36 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <8vfqv9$jif@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, ArcTan[x2-x2,y2-y2] ? Be careful with the argument order it is opposite to the atan2 function other languages. Regards Jens Blitzer wrote: > > I would like to find the angle between 2 points on the Cartesian plane. > However, if I use "ArcTan", it is not able to recognise that points with the > same x-coordinates have an angle of 90 degrees between them. It returns > "Indeterminate". > eg. for a point A (x1, y1) and a point (x1, y2), to find the angle between > them, I use ArcTan[(y2-y1)/(x1-x1)]. However, as the denominator is equal to > "0", this function returns "indeterminate". Is there a way to get around > this problem? Or is there other possible functions which can be used. > I am dealing with a very large array of numbers and thus, it's not possible > to check the coordinates individually. > > Would be grateful for any help rendered. Thanks! > > Derek