Ok, so the problem is about Optimization and I'm not really sure how to approach it.

Minimum CostAn industrial tank (two hemispheres and a circular cylinder) must have a volume of 3000 cubic feet. The hemispherical ends cost twice as much per square foot of surface area as the sides. Find the dimensions that will minimize cost.

Sadly I have only gotten the volume formula

π π

Any help would be appreciated. I'm not looking for a solution, but rather for a process. Thanks in advance.