- To: mathgroup at smc.vnet.net
- Subject: [mg3375] Re: ArcTan[x,y]
- From: withoff (David Withoff)
- Date: Sat, 2 Mar 1996 04:14:41 -0500
- Organization: Wolfram Research, Inc.
- Sender: owner-wri-mathgroup at wolfram.com
In article <4h13nr$rr4 at dragonfly.wolfram.com> Bill Freed <billf at math.concordia.edmonton.ab.ca> writes: > I am writing an article for a math education journal about the > conversion to and from polar coordinates. It would be useful to know > how the function ArcTan[x,y] is defined in Mathematica- by a single > formula, a Which statement or whatever? A rough description or the > Mathematica code would do. > > Thanks, > William Freed > > billf at math.concordia.edmonton.ab.ca > For non-zero machine real numbers, ArcTan[x, y] calls the C library function atan2(y, x). If you want to know how atan2 works you might need to find someone who knows how C library functions are typically implemented. Probably it's a bunch of "if" statements that eventually call something like atan(y/x) but I don't really know. In Mathematica, for arguments other than non-zero machine real numbers, it's a bunch of "if" statements that eventually call something like ArcTan[y/x]. Dave Withoff Research and Development Wolfram Research ==== [MESSAGE SEPARATOR] ====