A general geometry and calculus : including book I. of the general geometry, treating of loci in a plane; and an elementary course in the differential and integral calculus (1881)
Olney, Edward, 1827-1887 · New York : Sheldon and Co. · leaf 213
numerical value in the hyperbola. Sugs.—In case of the elhpse, let PE be thenormal at P and ED the subnormal. Now --—- = tan PE D, or -4— = —^,.E D Subnor B^x Subnor = ——.A Ex. 2. Show that in the parabola the subnormal is constant andequals the semi-parameter. Show how this property may be used… … 284. JPvop,—In the parabola a line joining the focus and the inter-section of a tangent with the axis of j {a tangent at the vertex), is per-pendicular to the tangent. Dem.—Let F be the focus, PT a tangent, andPE a normal. Join the intersection L with F.Then is FL perpendicular to PX. For, sinceAT…
Geometry, Analytic · Calculus
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