5. The point A, with coordinates (0, a, b) lies on the line l1, which has equation
r = 6i + 19j – k + (i + 4j – 2k).
(a) Find the values of a and b.
(3)
The point P lies on l1 and is such that OP is perpendicular to l1, where O is the origin.
(b) Find the position vector of point P.
(6)
Can somebody do an example with full working out for part b please? Thanks