1. Normal and Tangent to a Cassini Oval

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This Demonstration shows how to construct the normal and tangent to a Cassini oval at a point .


A Cassini oval is the locus of points such that , where and . If the foci and , then

, .

For the normal vector at a point on the oval,


where is the unit vector in the direction of .

Thus the normal to the Cassini oval at is a diagonal of the parallelogram obtained by extending the vector by and extending by , where . Then the tangent is the perpendicular to at .


Contributed by: Marko Razpet and Izidor Hafner (August 2018)
Open content licensed under CC BY-NC-SA



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