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!

Finding Limits

  1. Jan 18, 2014 #1
    1. The problem statement, all variables and given/known data
    Find the following limit

    lim (1/(x-1))-(2/(x^2-1))
    x→0


    2. Relevant equations



    3. The attempt at a solution
    I tried simplifying the equation into one fraction by finding a common denominator. I did this to try to get a denominator where I could plug 1 in without it equaling 0. It didn't work, i ended up with (x^2-2x)/(x^3-x^2-x+1). I feel like I went in the wrong direction from the beginning. If someone could tell me what detail I'm missing it would be greatly appreciated! Thanks!
     
  2. jcsd
  3. Jan 18, 2014 #2

    Mark44

    Staff: Mentor

    The LCD is x2 -1, not (x - 1) (x2 - 1). All you need to do is multiply the first fraction by x + 1 over itself.
     
  4. Jan 18, 2014 #3
    I did that which left me with (x - 1)/(x^2 - 1) but that still makes the expression undefined when I input 1. I know the answer is 1/2, but I still don't see it. Does the expression mean 1/2 and I'm missing it or is there more computation involved?
     
  5. Jan 18, 2014 #4

    Mark44

    Staff: Mentor

    There's a little bit more to do. Factor the denominator and cancel the common factors in top and bottom.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Finding Limits
  1. Find the Limit (Replies: 3)

  2. Find the limit (Replies: 15)

  3. Finding the Limit? (Replies: 1)

  4. Find the limit (Replies: 26)

  5. Find this limit? (Replies: 4)

Loading...