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Homework Help: Change of Variable

  1. Nov 26, 2007 #1
    [SOLVED] Change of Variable

    In case of the triangular area with vertices: (-1 1) (0 0) and (1 1), how would you do a change of variable to make that look like a square or rectangular region in terms of u an v?

    x = (1/2)(u+v) y = (1/2)(u-v)


    u = x+y v = x-y
  2. jcsd
  3. Nov 27, 2007 #2


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    No (continuous) change of variable will make a 3 sided region into a 4 sided region!
  4. Nov 27, 2007 #3
    oh. well what i did was to do the change of variable and then do the intervals as if i had a whole quadrilateral region and then i halved the answer. It seems to be right but i am not sure however.
  5. Nov 27, 2007 #4


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    Choosing u= x+y, v= x- y as coordinates will make two sides of the triangle, y= -x and y= x correspond to u= 0 and v= 0 respectively. The third side of the triangle, y= 1, becomes u+ v= 2.

    I have no idea what you mean by "intervals" or what answer you "halved". Apparently this was part of a larger problem you haven't mentioned.
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