Answer
The maximum value of $V$ is at $(6,3456)$ which means the value of $x$ which $V(x)$ is maximum is $6~in$.
The result is the same with part (c).
Work Step by Step
The sketch of the graph using a graphing utility is as shown.
Notice that the maximum value is at $(6,3456)$ which means the value of $x$ which $V(x)$ is maximum is $6~in$.
The result is the same with part (c).
