A cylinder is to be made of circular cross-section with a specified volume. Prove that if the surface area is to be a minimum, then the height of the cylinder must be equal to the diameter of the cross-section of the cylinder.

Question

A cylinder is to be made of circular cross-section with a specified volume. Prove that if the surface area is to be a minimum, then the height of the cylinder must be equal to the diameter of the cross-section of the cylinder. 
Maybe it's the wording, but I have not been able to crack this one for the past half-hour!

Reiny · Answer

Patience, You just posted the same question 5 minutes ago http://www.jiskha.com/display.cgi?id=1290049020