This may be a little OT, and I am embarrassed at having to ask this, but I
can't seem to find an equation that will allow me to draw an ellipse
(CENTERED ON THE ORIGIN) by stepping through an angle A. Given the x and y
axis radii, a and b, I want to start at zero angle and calculate a radius
measurement R (FROM THE ORIGIN) for that angle. My thinking is that I will
actually need to calculate x and y coordinates of the point on the ellipse
for the angle A, then take the square root of the sum of the squares of a
and b (did you follow that??). The angle A will step at some given interval,
say 5 degrees, all the way around the horn to 360. Eshabach's Handbook of
Engineering Fundamentals says the parametric form is:

y = b*sin(A)
x = a*cos(A)

My own scribblings got me to:

y = a*sin^2(A)
x = b*cos^2(A)

Anyone have any suggestions?

Jon

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