Plane and solid analytic geometry; an elementary textbook (1905)
Ashton, Charles H. (Charles Hamilton), 1866- · New York, C. Scribner's Sons · leaf 125
ine DR^ has been called the directrix, and thepoint F the focus. Place the points F and D on theX-axis so that OF=F0 and OD = I)0, and draw DHperpendicular to the X-axis. The symmetry of the curve 108 ANALYTIC GEOMETRY [Ch. IX, § G5 shows that if we had used the line BH and the point F asdirectrix… … We can now obtain the relations between the variouslines in the figure. We have seen that FD = DF = m, m CA = A0 =a = CB = B0 =h em 1-^2 em VI It follows that CD = -, and tliat the equations of thedirectrices are a^ = % and 00 = -^. [38] e e Cii. IX, § 65) CONIC SECTIONS 109 m Also that CF=^CD-FD =…
Geometry, Analytic
Internet Archive · Boston Library Consortium · Public Domain Mark 1.0. Free to use for anything.
