題目
Problem
甲、計算、證明題：共 2 題，每題 10 分，共 20 分。須詳細寫出計算及證明過程，否則不予計分。
- A manufacturer of aquariums wants to make a large rectangular box-shaped (an open rectangular box) aquarium that will hold 64 cubic feet of water. If the material for the base costs $20 per square foot and the material for the sides costs $10 per square foot, find the dimension for which the cost of the materials will be least.