Hi,

The problem is:

given a cylinder (I prefer beer can) holding 1000 cubic cm. What should the radius and height be to minimise the surface area.

I have tried the following

therefore,

and

subsitituting (h), and simplifying

derive that to get:

Solving for r when S'=0 (critical point), I obtain.

, which according to the text book is correct. Great news. Now I get stuck...

I cannot get h correct. For some reason h is .

I am so close yet cannot figure out how to get that result.

Subsituting r into the original equation for h gives:

This is not correct.

Thanks

Craig.