Plane and solid analytic geometry; an elementary textbook (1905)
Ashton, Charles H. (Charles Hamilton), 1866- · New York, C. Scribner's Sons · leaf 153
tly the case here,since the tangent to the ellipse bisects the exterior angle 136 ANALYTIC GEOMETRY [Cii. X, § 78 between the focal radii, and the tangent to the liyperbolabisects the interior angle. The curves therefore intersectorthogonally. 4% The tangent at any point of a parabola onakes… … Fig. 73. to OX. We wish to prove that the angles TP^P andFTP^ are equal. If we let the abscissa of P^ be x^^ its ordinate will be± V2 mx^^ since P-^ is a point on the parabola. Then theequation of the tangent at P^ is ± V2 mx-^ » y = m(x -{- x^.If in this equation we let ?/= 0, we find the…
Geometry, Analytic
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