Plane and solid analytic geometry; an elementary textbook (1904)
Ashton, Charles Hamilton, 1866-1936 · New York, C. Scribner's Sons · leaf 153
s evidently the case here,since the tangent to the ellipse bisects the exterior angle 136 ANALYTIC GEOMETRY [Ch. X, § 78 between the focal radii, and the tangent to the hvperbolabisects the interior angle. The curves therefore intersectorthogonally. 4. The tangent at any point of a parabola makes… … Fig. 73. to OX. We wish to prove that the angles TPXF andFTPX are equal. If we let the abscissa of Px be xv its ordinate will be± V2 mxv since Px is a point on the parabola. Then theequation of the tangent at Px is ± ^/2mx1 • y = m (x + x^). If in this equation we let y = 0, we find the interceptOT…
Geometry, Analytic
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