Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 138
ibe circles of radii a = OA andb = OB, with the origin 0 as thecommon center. Draw any ray from0, making an angle <^ with the posi-tive axis of X, as shown in the Zfigure. Through the points Q and Bdraw the parallels indicated. Theirpoint of intersection, P, will lie onthe ellipse. For, if the… … Fig. 15 Hence (2) ^ + ^ = 1.a2 62 Conversely, any point {x, y) on the ellipse (2) has corre-sponding to it an angle <^, for which equations (1) are true. Equations (1) afford what is known as a parametric repre-sentation of the coordinates of a variable point {x, y) of theellipse in terms of the…
