Corollary C is derived from $E_(x) = \frac{f''(x)}{2} \cdot (x-a)^2$
I'm having serious issues understanding this problem and I'm just not getting it right. I'm preparing for a test so this isn't really 'homework' so you can give as hard hints as you want. Thanks!
Perhaps it would more visual if it was related to mechanics:
Let $f(x)$ be the position of your car at time $x$, you have initial conditions which are :
at time $x = 2$, you are at position $4$, that's $f(2) = 4$.
at time $x = 2$, you are moving with speed $-1$, that's $f'(2) = -1$.
For any time $x$, you have acceleration in the range $[0, \frac1x]$, that's $0 \le f''(x) \le \frac1x$.
Question is : Where can you be at time $x = 3$?