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Homework Help: Limit help(1/rad(x) - 1/rad(x^2 + x))

  1. Sep 24, 2011 #1
    1. The problem statement, all variables and given/known data

    lim x->0+ 1/x1/2 - 1/(x2+x)1/2

    2. Relevant equations

    inf - inf

    3. The attempt at a solution

    I can't get x out of the bottom of the equation.
  2. jcsd
  3. Sep 24, 2011 #2
    I have manipulated the equation to:

    x1/2(x+1) - (x2+x)1/2 / x(x+1)
  4. Sep 24, 2011 #3
    Which I now was able to reduce to:

    x(x1/2-x) / x(x+1)

    which goes to:

    (x1/2-x) / (x+1)

    and so my limit is 0/1 which is zero.

    Anyone want to check the work I would greatly appreciate it.
  5. Sep 24, 2011 #4
    Yeah, that limit is tending to 0. It's important that it's from the positive side because of the domain of the radicals.

    I simply combined the fractions and the limit went to the indeterminate form 0/0. Then I just L'Hopital ruled it into 0/1
    Last edited: Sep 24, 2011
  6. Sep 24, 2011 #5


    Staff: Mentor

    This is not an equation - it's an expression. An equation has two expressions that are connect by =.
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