Hi, I have no idea how to show the answer to this problem:

Let S be the interior of the plane bounded by the graphs of the two functions y=x^2 and y=|x|. Prove that the conclusion of the MVT fails in this region. That is select two points a and b and design a function f that satisfies that f is continuous and differentiable on S but the conclusion of the MVT fails.

Thanks a lot!