1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Indeterminant limit (radical in denominator)

  1. Nov 19, 2007 #1
    1. The problem statement, all variables and given/known data

    [tex]\lim_{x \to {4}}\frac{4 - x^2}{2 - \sqrt{x}}[/tex]

    2. Relevant equations

    3. The attempt at a solution

    [tex]\lim_{x \to {4}}\frac{4 - x^2}{2 - \sqrt{x}} \cdot \frac{2 + \sqrt{x}}{2 + \sqrt{x}}[/tex]

    [tex]= \frac{x(4-x)(2-\sqrt{x})}{(4-x)} = x(2-\sqrt{x}) [/tex]

    this equals zero, but is the limit indeterminate at this point?
    Last edited: Nov 19, 2007
  2. jcsd
  3. Nov 19, 2007 #2


    User Avatar
    Homework Helper

    I think you expanded the numerator incorrectly
  4. Nov 19, 2007 #3
    thanks! it was a missed minus sign.
  5. Feb 15, 2010 #4
    4-x^2 = (2-x)*(2+x)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook