Thanks I got it now. Also, I've been stuck on this one. I know the co-ordinates are right
(\frac{ap^2(p+1)}{p^2+1},\frac{ap^3(p+1)}{p^2+1})
Can someone help me turn that into a locus equation. I know I have to let the x-coordinate equal x and then make the subject p, then sub it into y, but...