It can be shown that if |d2y / dx2| M on a closed interval with c

Question:

It can be shown that if |d2y / dx2| ≤ M on a closed interval with c and c + Ax as end points, then
|Δy - dy| ≤ 1/2M(Δx)2
Find, using differentials, the change in y = 3x2 - 2x + 11 when x increases from 2 to 2.001 and then give a bound for the error that you have made by using differentials.