[R] Ellipse: Major Axis Minor Axis

[Vishal]

I have a matrix(3000x2) of numbers and I have plotted a scatterplot
(defined in the ``car'' library.)

scatterplot(r$V1,r$V2,ellipse=TRUE)

The ellipse plotted is an error ellipse.

I want the find the major(semi), minor(semi) minor axis length of this
ellipse.
Does anybody know how to do it?

I can get the center of this ellipse using the cov.trob function
(defined in ``MASS'' library),
and with some formula, also the Angle of Rotation of the error
ellipse.

Any help on finding the major, minor axis lenght of the ellipse
greatly appreciated!!

Thank you!

Vishal.