The Mean Value Theorem : In this section we will discuss the Mean Value Theorem. 

Before we going through the Mean Value Theorem we have to cover the following theorem.

Rolle's Theorem : Assume f ( x ) is a function which satisfies all of the following.

1. f ( x ) is continuous on the closed interval [a,b].

2. f ( x ) is differentiable on the open interval (a,b).

3. f ( a ) =f (b )

Then there is a number c such that a < c < b and f ′ (c ) = 0 .  Or, in other terms f ( x ) contain a critical point in (a,b).