Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 424
g on L. 2. Projection of a Broken Line. Given a point P and a lineL in space. The projection of P on i^ is defined as the foot, 31,of the perpendicular dropped from Pon L, or as the point 3f in which theplane p, passing through P perpen-dicular to L, meets L. If P lies onL, it is its own projection… … Fig. 1 406 ANALYTIC GEOMETRY If p and q are the planes through P and Q perpendicular toL, the projection, MN, of PQ on L is equal to the directed line-segment intercepted by the planes p and q on any parallel to L.For example, it is equal to the directed line-segment PR in Fig. 1* Consider a broken…
