Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 137
rabola. If, then, in theequation we allow e toapproach 1 through values< 1, the ellipse which theequation defines ap-proaches a parabola as itslimit. We can visualize theellipse, going over intoa. parabola, by drawinga number of ellipseshaving the same value ofbut having values for c which are… … Fig. 14 m,as THE ELLIPSE 119 A of each successive ellipse are farther away from O, andtheir distances from 0, namely, m 00 = 1- OA = m1^ i \ increase without limit. Thus, as e approaches 1, the ellipseapproaches as its limit the parabola whose directrix is D andwhose focus is F. 10. New Geometrical…
