posted by sh .
To construct a tincan, V=32pi m^3, The cost per square meter of the side is half of the top and bottom of can. What are the dimensions and the cost?
Let x be the cost, I subbed 32/r² for h
f'(r)=4πxr + 32xπ/r²
I factored, it, r=-2, which is not in the domain.
Where did it go wrong?