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Surface area of a plane

  1. Nov 25, 2011 #1
    SECOND EDIT: Never mind I think I figured it out. My problem was assuming the shape was a square. It was a rhombus. Thanks anyways guys

    This isn't a homework problem, just something I was thinking of. Let's say I have the plane z= x+y and I wanna find the area of the region from 0≤x≤2 and 0≤y≤2

    ∫∫√[(1+(f[itex]_{x}[/itex])2 + (f[itex]_{y}[/itex])2] dA

    (the f subscripts are partial derivatives)

    Would give me an answer of 4√3

    But just using geometry I think the portion of the plane would just be a square with sides of √8
    giving me an answer of 8.

    Where'd I go wrong?

    EDIT: I realized this probably belongs in another section, but as far as I can tell I can't delete this thread, so please feel free to move it if its not appropriate here.
    Last edited: Nov 25, 2011
  2. jcsd
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