so (x,y) lie on the parabola y = x^2
therefore (x,y) can be written as (x,x^2)
assuming the q is talking about its perpendicular distance to that line
distance = | x - x^2 -1| x (1 + 1)^-1/2
= |x^2 -x +1| x 2^-1/2 (dividing by -1 this wont affect the answer since there are absolute value...