Question: A closed box with a square base is to have a volume of 250 cubic meters. The material for the top and bottom of the box costs $2 per square meter. The material for the sides cost $1 per square meter. What is the minimum cost of constructing the box? Let x be the width of the square base and y the dimension of the height. The volume of the box is the area of the base times the height. As always, let x be the independent variable.

Target function f(x):
Domain of f(x) _____
Domain of f(x)__________
Exact value of 2nd derivative at critical value of x:

Max. or Min. value of f(x)___________