littlehelp?
(a) Given the points (4,0), B (-2,0) and P (x,y), find the gradients of AP and BP.
AP = y/x-4
BP = y/x+2
(b) Hence show that the locus of the point P(x,y) that moves so the angle APB is a right angle has equation x^2 + y^2 - 2x - 9 = 0.
(c) Complete the square in x, and...