We need to make an open topped box with a square base and fixed volume of 8 cubic feet.

Question

The material for the base costs $ 6 per square foot and the material for the side costs $4 per square foot. Write a function for the cost as a function of the length and side of the base

Answer 1

each side of the base ---- x ft
height of box ------------ y ft
x^2 y = 8
y = 8/x^2

cost = 6x^2 + 4xy
= 6x^2 + 4x(8/x^2)
cost = 6x^2 + 32/x