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Homework Help: Problem Calculating a limit with a square root, i'm stuck

  1. Jan 21, 2010 #1
    Problem Calculating a limit with a square root, i'm stuck :(

    1. The problem statement, all variables and given/known data


    The limit is equation 9-t / 3-sqrt(t) as t approaches 9

    I'm stuck on the how to simplify this?

    Thanks for any help.


    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 21, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    Re: Problem Calculating a limit with a square root, i'm stuck :(

    Try multiplying by (3+√t)/(3+√t)
     
  4. Jan 21, 2010 #3
    Re: Problem Calculating a limit with a square root, i'm stuck :(

    I discovered that that is the conjugate and I came out with this:

    27-6sqrt(t)-tsqrt(t)
    ----------------
    9-t

    So in other words, that limit does not exist. Is that right?
     
  5. Jan 21, 2010 #4

    Mark44

    Staff: Mentor

    Re: Problem Calculating a limit with a square root, i'm stuck :(

    The limit does exist. Instead of multiplying by the conjugate over itself, just factor the numerator, treating it as the difference of two squares.
     
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