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Question about the minimum area

  • Thread starter Lord Dark
  • Start date
  • #1
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Homework Statement


hi guys, how are you all,,
my friend had a quiz and he told me about this question :
container has a square base and the volume of it V= 1000 , find the minimum area of the surface that the container can have ...


Homework Equations


A=x^2 , V=x^2 * h


The Attempt at a Solution


i started by saying: 1000=x^2 * h then i can get h =1000/x^2 and A=x^2 then i differentiate 0=2x*h+x^2*h` ... i get at the end (2000/x)-(2000/x)=0 and this doesn't make any sense ,,i tried another way ,, i assumed it should be a cube for the minimum area so i get 6x^2=1000 then i get (x=13) is the answer right?? ,, is the question even right ?? anyone knows how it should be at least ??
 
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Answers and Replies

  • #2
27
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By minimum area, do you mean the sum of the area of the six surfaces? Are there six, is the top included?
Often these questions are asked to minimise material for packaging to hold a certain volume which I'd say this question is about. Not sure though...
 
  • #3
121
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i really don't know ,, he didn't remember ,, although, if it was the minimum area of the surface of the container ,, it should be cube right ?? so can i apply this equation ?
(6x^2=1000) ??
 
  • #4
121
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i think i got it ,, can anyone check my answer now ,,

1000=x^2*y , y=1000/x^2 , surface area = 2x^2+4x*(1000/x^2) then differentiate i get 4x-(4000/x^2)=0 then i get x=10 and y=10 so it's cube alright :D
 

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