[R] drawing ellipses in R
Barry Rowlingson
b.rowlingson at lancaster.ac.uk
Tue Nov 1 09:44:04 CET 2011
On Tue, Nov 1, 2011 at 4:49 AM, <mmstat at 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
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