Question: Find the dimensions giving the minimum surface area, given that the volume is 8 cm3.
1. A closed rectangular box, with a square base x by x cm and height h cm.
2. An open-topped rectangular box, with a square base x by x cm and height h cm.
3. A closed cylinder with radius r cm and height h cm.
4. A cylinder open at one end with radius r cm and height h cm.