Analytic geometry and principles of algebra (1913)
Ziwet, Alexander, 1853-1928, Hopkins, Louis Allen, joint author, Hedrick, E. R. (Earle Raymond), 1876-1943 · New York, The Macmillan Company · leaf 214
he fixed points i^i, Fo are again called the foci; if 2 a is the constant difference, every point P of the hyperbola must satisfy the condition F.2P-F,P=±2a. Notice that the length 2 a must here be not greater than thedistance FoF^ = 2 c of the foci. The curve is symmetric to the line FoF^ and to… … Fig. 85 straightedge at Q and with its other end to the other focus,F^. As the straightedge turns about Fo, the string is kepttaut by means of a pencil at P which describes the hyperbolicarc. Of course only a portion of the hyperbola can be tracedin this manner. 208. Equation of the Hyperbola. If…
Geometry, Analytic
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