Question

optimization problem

http://gyazo.com/1c87eaef5625a48e8cb88877f822cd14

Answer 1

Start with formulas for Volume and Surface Area

Answer 2

I know how to start the problem. V = B*L*H

Answer 3

16=2x^2*H

Answer 4

H=8/x^2

Answer 5

SA=2(2x^2)+2(xh)+2(2xh)

Answer 6

replace all h's with 8/x^2

Answer 7

simplify, and then take the first derivative, set the derivative equal to zero and solve

Answer 8

but im messing up somewhere along the line. since the answer i get is 1.817

Answer 9

which is wrong

Answer 10

any luck? '_'

Answer 11

Suggestion: Be WAY more deliberate and organized. In particular, more meaningful names of variables will help.

Base Cost = $8 / m^2
Sides and Lid Cost = $16 / m^2

You have not included this information.

Answer 12

informations all in the pic i have posted. :L

Answer 13

Perhaps I should be more clear. Your formulation includes ONLY the area of the materials. It does NOT include the COST of the materials.

This is fine for surface area, but insufficient for cost.
SA=2(2x^2)+2(xh)+2(2xh)

Cost of Base
(2x^2) * 8

Cost of Sides and Lid
[(2x^2)+2(xh)+2(2xh)] * 16

Also, it would help if you would be more specific. "I got 1.817" is not very meaningful. "I got x = 1.817" would be better. It would be even better if you had formally defined 'x' at some point.

Answer 14

ty. didnt realize i had to put cost formula in as well.

Answer 15

got the right answer now. '_'