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Domain of a function

  1. Apr 6, 2008 #1
    for g(x) = (x-2) / (x^2 -9)

    the domain of the function would be simply to have the denominator not equal to 0, which in this case would be x = 3.

    but.. the solution states that it is -3 and 3 cannot be used.

    this is confusing seeing that -3^2 -9 = -18 which is not 0.

    maybe it means |-3|?
     
    Last edited: Apr 6, 2008
  2. jcsd
  3. Apr 6, 2008 #2
    (-3)^2 - 9 = 9-9 = 0

    there is a difference,

    -3^2 = (-1)*3^2 = -1*9 = -9, but (-3)^2 = (-1*3)^2 = (-1)^2 * 3^2 = 1*9 = 9
     
  4. Apr 6, 2008 #3
    i get it. thanks
     
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