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Homework Help: For what values of x is │x^2-4│ not differentiable?

  1. Apr 17, 2005 #1
    For what values of x is │x^2-4│ not differentiable?
    Is there a way to solve it without looking at the graph?
  2. jcsd
  3. Apr 17, 2005 #2


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    Yep. Differentiate it and see where the derivative doesn't exist.
  4. Apr 17, 2005 #3


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    You have to use the definition of the derivative (the limit).

    Notice how limit from the right and limit from the left are different as x approaches -2 and +2 from both sides.
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