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Homework Help: Little Calculus help

  1. Dec 12, 2004 #1
    Hello, the problem that i can't figure out says: To Use LaGrange multipliers to find all points on the ellipse 8x^2 + 2y^2 = 16 at which the product xy is a minimum? Any hints appreciated.
     
  2. jcsd
  3. Dec 12, 2004 #2

    Hurkyl

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    What have you done so far?
     
  4. Dec 12, 2004 #3
    I'm just not sure what the "which the XY product is a minimum" is really asking me.
     
  5. Dec 12, 2004 #4

    Hurkyl

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    xy is your objective function, the one you're trying to minimize.
     
  6. Dec 12, 2004 #5
    to have a minimum of a function the 1st derivative must equal 0 and the second derivative must be greater than 0.

    does that help?
     
  7. Dec 12, 2004 #6
    ah ok, and my ellipse is the constraint then?
     
  8. Dec 12, 2004 #7

    Hurkyl

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    Looks that way.
     
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