Osgood, William F. (William Fogg), 1864-1943, Graustein, William Caspar, 1888-1941, joint author · New York, The Macmillan company · leaf 48
or both of the lines has no slope, i.e. is parallel to theaxis of y. 8. Distance of a Point from a Line. Let P:(xly tfa) be agiven point and let L: Ax + By+C = 0 be a given line. To find the dis-tance, D, of P from L. Drop a perpendicular from Pon the axis of x, and denote thepoint in which it cuts… … Fig. 8 y« Hence(1) QP B Axx + Byx + CB Let 6 be the slope-angle of L and form the product QPcos0.One or both of the factors of this product may be negative,according to the positions of P and L* But always thenumerical value of the product is equal to the distance D: (2) Z)=|QPcos0|. This is clear…
Geometry, Analytic
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
