Young, George, jr, Baxter, Hubert Eugene, joint author · New York, The Macmillan Co. · leaf 149
rpendicular tothe axis. Lay offvc equal to vb. Therequired tangent isthe line ca. Second method,using the focus.Let d be the re-quired point oftangency. Thefocus, /, can be de-termined by § 117.Lay off vz = vf, anddraw the directrix, xy. Connect d with the focus, /. Drawdg parallel to the axis and… … Fig. 128 VII, § 120] CURVED LINES 133 radius, draw a circle tfw intersecting the directrix at t and w.Perpendiculars to the directrix drawn from these points willintersect the parabola at q and u which are the required pointsof tangency. 119. To draw a Normal to a given Parabola. First method. One…
Geometry, Descriptive
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