Any point P on the given line is (r,2r + 1,3r + 2) direction ratios of AP are (r - 1, 2r - 5 ,3r - 1) Now AP ⊥ to the given line if 1(r - 1) + 2( 2r - 5) + 3 (3r - 1) = 0 ⇒ 14r -14 = 0 ⇒ r = 1 ∴ P is (1,3,5). Thus the foot of the ⊥ from A on the line is (1,3,5). Let be the image of A in the given line. Then P is the mid point of AB. ∴
