The answer I think is D but use the app photo math very useful:)
Answer:
This contradicts the Mean Value Theorem since there exists a c on (1, 7) such that f '(c) = f(7) − f(1) (7 − 1) , but f is not continuous at x = 3
Step-by-step explanation:
The given function is

When we differentiate this function with respect to x, we get;

We want to find all values of c in (1,7) such that f(7) − f(1) = f '(c)(7 − 1)
This implies that;




![c-3=\sqrt[3]{63.15789}](https://tex.z-dn.net/?f=c-3%3D%5Csqrt%5B3%5D%7B63.15789%7D)
![c=3+\sqrt[3]{63.15789}](https://tex.z-dn.net/?f=c%3D3%2B%5Csqrt%5B3%5D%7B63.15789%7D)

If this function satisfies the Mean Value Theorem, then f must be continuous on [1,7] and differentiable on (1,7).
But f is not continuous at x=3, hence this hypothesis of the Mean Value Theorem is contradicted.
First, we determine the volumes of the posts may it be cylindrical in shape or rectangular prism.
(A) cylindrical:
( π(26.7/100)² - π(24.2/100)²)*(7.5) = 0.3 m³
(B) rectangular prism:
(40/100)²(7.5) - (35/100)²(7.5) = 0.28125 m³
Then, we calculate for the amount of substance
(A) cylindrical: (0.3 m³)(2700 kg/m³) = 810 kg
(B) rectangular prism : (0.28125 m³)(2700 kg/m³) = 759.375 kg
Then, calculate for the costs
(A) (810 kg)($0.38/kg) = $307.8
(B) (759.375 kg)($0.38/kg) = $288.56
Thus, the answer for A is rectangular post
B. About $19.24 can be saved.