

An ellipse can be defined as the locus of points, the sum of whose distances to two fixed points (the foci) is constant. This is the elementary “two ...



With given semimajor axes and semiminor axes, we can define two foci, and therefore an ellipse, that will satisfy those axes.



The foci have the property that the lines from the foci to a point on the curve make equal angles to the tangent. Hence, light shone from one focus r...



The subnormal to point C on the curve is the segment from the intersection of the normal at C with the major axis, to the foot of the perpendicular dr...



Given a point (the focus) and a line (the directrix), we examine the locus of the points whose distance from the focus is k times the distance from th...



Where does the normal intersect the major axis?



Given a point D in an ellipse, draw a chord through D. Find the intersection of the the tangents at the end of the chord. The locus of all such inters...



A pair of diameters is conjugate if each is parallel to the tangents at the ends of the other. We show that the diameters of points whose parameters ...



