Originally Posted by

**dipsy34** I've been given a problem and would like to see if I have thought correctly when solving it. A box without lid with a volume of 4dm^{3} should have as small area as possible for the 5 limiting sides. the base should be square.

My solution: The base area is b^{2 }and the area for the 4 sides are b*h so total side area is 4*b*h. For the volume 4 we get that b^{2}*h = 4 so h = 4/b^{2}.

The total area is A = b^{2}+4*b*(4/b^{2}) -> A = b^{2} + 16/b.

Derivating and skissing the curve I found b=2 to be a minimum so with b=2 would therefor result in the least amount of materials used. Is this the correct steps for solving this type of problem?