An introduction to projective geometry and its applications; an analytic and synthetic treatment (1905)
Emch, Arnold, b. 1871 · New York, J. Wiley & sons; London, Chapman & Hall, limited · leaf 124
Figs. 42 and 43, according as we take for K an ellipse or an hy- THEORY OF CONICS. in perbola. Both curves are symmetrical with respect to both axes./CD he ratios I ) are therefore the same for both foci and their corresponding polars (directrices). Taking any point A on K anddesignating the focal… … Fig. 43- d+ dx = constant, and in an hyperbola d— dx = constant. Hencethe theorem: The sum of the radii vectores {AF, AFt) of any point of anellipse is constant. The difference of the radii vectores of an hyperbola is constant.In both cases the constant is equal to the distances of the vertices…
Geometry, Projective · Geometry, Analytic
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