Plane and solid analytic geometry; an elementary textbook (1904)
Ashton, Charles Hamilton, 1866-1936 · New York, C. Scribner's Sons · leaf 126
see that BF, being the hypotenuse of aright triangle whose legs are c and 5, is equal to a. Italso shows that a isalways larger than b, orthat ii(=2a), theaxis perpendicular to thedirectrices, is larger thanBB(=2b). AA hasbeen called the trans- x~verse or principal axis;BB is called the conju-gate… … 110 ANALYTIC GEOMETRY [Ch. IX, § GO All the formulas found above hold for [41], except theequations of the directrices, which are , a y = ±- e PROBLEMS 1. Find a, b, c, e, and the equations of the directrices in theellipse, (a) 4a2 + 9?/2 = 36, (b) 9x* + 4:y2 = ?>6, (c) 3ar° + 8>/2=10. 2.…
Geometry, Analytic
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