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!

Limits question

  1. Nov 6, 2007 #1
    1. The problem statement, all variables and given/known data
    lim
    x->1 [tex]\frac{tan^{-1} (x - pi/4)}{x -1}[/tex]

    2. Relevant equations
    None that I know of


    3. The attempt at a solution
    Indeterminate form, so use L'Hopital's rule

    Differentiate the top, then differentiate the bottom.
    The differential of the denominator is just 1.
    However I have no idea how to differentiate the numerator.

    Thanks for any help
     
  2. jcsd
  3. Nov 6, 2007 #2
    derivative of arctan(u) is: 1/(1+u^2)
     
    Last edited: Nov 6, 2007
  4. Nov 6, 2007 #3
    [tex]\frac{d}{dx}tan^{-1} (x) = \frac {1}{x^2+1}[/tex]
     
  5. Nov 6, 2007 #4
    Thanks guys.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Limits question
  1. Limit question ! (Replies: 2)

  2. Limit question (Replies: 10)

  3. Limits question (Replies: 6)

  4. Limit question (Replies: 3)

  5. Limits question (Replies: 5)

Loading...