Originally Posted by

**painterchica16** Hey there. I basically understand the whole method behind these kinds of problems but on one question in particular I am stuck as to how to set up the equation.

There is a solid formed by joining a hemisphere (half a sphere) to each end of a right circular cylinder. The Volume must be 3000 **cubic **feet. The hemispherical ends cost twice as much as the surface area of the sides. i have to find the dimensions that minimize the cost.

For V i set up the equation v= 4/3(pi)(r^**3**) + (pi)(r^2)(h)

Is this right? If it is, what variable do i set the equation equal to, h or r?

Finally, can someone explain how to come up with the cost equation?

After that I can take it from there, hopefully. Thanks