At least, I think that's what this question is asking for.
"The total cost to build an open box with a constant volume V and with a square base is given by the function
where x is the length of the square base.
a) Find the value of x that will produce the box with the minimum total cost. Your answer will involve the parameter of V.
b) Verify that this value of x will give the local minimum.
c) Give an argument based on calculus why this value of x actually gives a global minimum, not just a local minimum."
I'm not sure how to start.
Any help, please?