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Homework Help: Limit question

  1. Jan 15, 2007 #1
    1. The problem statement, all variables and given/known data

    lim sqrt(x^2-9)
    x->3


    2. Relevant equations

    I understand that the radical will evaluate to 0. I am not sure if the answer to the limit is 0, or undefined


    3. The attempt at a solution

    lim sqrt((3)^2-9) = sqrt(9-9) sqrt(0) = 0
    x->3


    Thanks for your help.
     
  2. jcsd
  3. Jan 15, 2007 #2

    Hootenanny

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    What is the requirements for a limit to exists?
     
  4. Jan 15, 2007 #3
    The limit coming from both sides, must approach the same y-value. In this case 0. The function will never hit 0, but will get infinitely close. That would make the value of the limit 0??
     
  5. Jan 15, 2007 #4

    Hootenanny

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    Correct :approve:
     
  6. Jan 15, 2007 #5
    Good deal. I thought that was it. Wanted to be 100% sure.
     
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