On Tue, Nov 1, 2011 at 4:49 AM, <mms...@comcast.net> wrote: > Hello, > > I have been following the thread dated Monday, October 9, 2006 when Kamila > Naxerova asked a question about plotting elliptical shapes. Can you explain > the equations for X and Y. I believe they used the parametric form of x and y > (x=r cos(theta), y=r sin(theta). I don't know what r is here ? Can you > explain 1)the origin of these equations and 2) what is r? >
The origin of these equations? Probably this guy: http://en.wikipedia.org/wiki/File:God_the_Geometer.jpg Or maybe Euclid. What is r (as opposed to R)? Mathematical questions are nicely answered by Mathworld: http://mathworld.wolfram.com/Circle.html - a fantastic resource for maths and stats information. Barry ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
