Question

A rectangular tank with no top made from stainless steel.The volume of the box is 250 cm^3.The base is a square with sides x cm.The material for the bottom will cost RM 2 per cm^2 and the material for the sides will cost RM 4 per cm^2.

Answer 1

i know that the volume is x^2y = 250.
then let y
y= 250 / x^2
then how to calculate it's minimum cost??

Answer 2

hehe...i hope no racist here

Answer 3

volume = x^2h = 250
let h
h = 250 / x^2
area = base + 4 ( lenth x height)
area = (x^2) 2 + 4 ( 4x * 250/x)

A = 2x^2 + 4000 / x
differentiate A' = 0
4x - 4000/ x^2 = 0
x = 10
therefore
minimum cost = 2 (10)^2 + 4000/ 10
= 600