Lagrange Multiplier----to find out the dimensions when metal used min. 1. The problem statement, all variables and given/known data I have a rectangular tank with a capacity of 1.0m^3. The tank is closed and the cover is made of metal half as thick as the sides and base. Find the dimensions of the tank for the total amount of metal used to build be minimum. 2. Relevant equations Lagrange f(x)-λ(xyz-1)=g(x,y,z,λ) 3. The attempt at a solution the constraint is xyz=1, but what should I use for f(x)? Please guide , thank you.