Test the mean value theorem on the function f (x) = x³ − x, defined over [0, 2].
We find that [f (2) − f (0)]/(2 − 0) = 3 and f^{\prime}(x) = 3x^{2} − 1. The equation f^{\prime}(x) = 3 has two solutions, x = ±2\sqrt{3}/3. The positive root x^{∗} = 2\sqrt{3}/3 ∈ (0, 2), and
f^{\prime}(x^{*})={\frac{f(2)-f(0)}{2-0}}This confirms the mean value theorem in this case.