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Homework Help: Optimization - area of rectangle

  1. Jan 11, 2010 #1
    1. The problem statement, all variables and given/known data
    If the perimeter of a rectangle is fixed in length, show that the area of the rectangle is greatest when it is square


    2. Relevant equations



    3. The attempt at a solution
    if the perimeter is fixed in length, then 2x + 2y = c
    then no idea to continue from there
     
  2. jcsd
  3. Jan 11, 2010 #2

    Dick

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    Re: differentiation

    Ok so far. Now you want to maximize x*y, right? Eliminate one of the variables using the perimeter condition and differentiate, etc.
     
  4. Jan 11, 2010 #3

    rock.freak667

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    Re: differentiation

    So what is the area A in terms of x and c?
     
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