1. The problem statement, all variables and given/known data Find the point on the parabola y^2 = 2x that is closest to the point (1,4) 2. Relevant equations d = ((x-1)^2 + (y-4)^2)^1/2 x=y^2/2 3. The attempt at a solution My attempt involves subbing in x in the d equation and differentiating it. I cant get the same answer as the book because they differentiate d^2 = not d = to make it easier to solve. They state "you should convince yourself the minimum of d occurs at the same point as the minimum of d^2, but d^2 is easier to work with" How do i know it occurs at the same point?