Hi everyone. I hope I've found the right place for my first post here. I have a geometry problem which I need to solve for a piece of software I'm writing, and I'm hoping someone might be able to help me.(adsbygoogle = window.adsbygoogle || []).push({});

I have a non-rotated ellipse inside a circle, as in this diagram. I know the x and y coordinates for the centres of both the circle and the ellipse, and I know the radius of the circle and the width and height (major and minor axis) of the ellipse. This is also a special case of circle-ellipse intersection, in that the edges of the ellipse just touch the inside of the circle to form two tangents, both at the same height above the x-axis.

http://andromedus.com/misc/ellipse.jpg [Broken]

What I need to find out is the y coordinate of P, the vertical point of intersection.

I have found this page: http://mathworld.wolfram.com/Circle-EllipseIntersection.html which goes some way to helping me, but unfortunately I don't know get from there to a single equation in terms of the value I need to calculate - the vertical point of intersection.

Any help is much appreciated - thanks! :)

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# Ellipse inside a circle - intersection

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