Osgood, William F. (William Fogg), 1864-1943, Graustein, William C. (William Caspar), 1888-1941, joint author · New York : The Macmillan Company · leaf 283
ocus. Example 2. A straight line L passes through a fixed pointPq ; find the locus of the mid-point P of the portion of L inter-cepted by two given perpendicu-lar lines, neither of which goesthrough Pq. Take the two given lines asaxes, and let the coordinates ofPq, referred to them, be {xq, y^).The… … (x,r) XX Fig. 2 iliary variable. The equation of L is, then, 2/ - 2/0 = >. (^ - ^^^o)-The coordinates of the points of intersection of L with the axes are: A.(xQ-y^,o), A B :■{(), Vq-Xxq). Hence the coordinates of P, the mid-point of AB, are ^-1--!. Y=h{yQ-^^^) To eliminate X from these two…
