Cylindrical optimization problem

wapakalypse
Messages
3
Reaction score
0
A closed cyliindrical container has a volume of 5000in^3. The top and the bottom of the container costs 2.50$in^2 and the rest of the container costs 4$in^2. How should you choose height and radius in order to minimize the cost?


v=pi(r)^2



Unfortunately my attempt at this problem is feeble.
I have trouble finding two equations.
past that, i can derive them and solve.
any help would be most appreciated,
thankss
 
Physics news on Phys.org
Write an equation using the fact that the volume of the cylinder is known.
This will help you relate height and radius of the container.
Use this in the expression to be minimized.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top