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 the derivative

  1. Apr 3, 2009 #1
    1. The problem statement, all variables and given/known data
    Sketch the graph of the function f(x)=(2(x^2+1)^1/2)/(x-1)

    2. Relevant equations
    All the derivative simplification rules

    3. The attempt at a solution
    The only part of the question I need help with here is finding the derivative of this function. In my book it says the derivative is f'(x)=(-3(x+1))/((x-1)^2(x^2+1)^1/2), but all I can get is f'(x)=(2x(x-1)-2(x^2+1)^1/2)/((x-1)^2(x^2+1)^1/2). I don't know how to go about simplifying this any further. Any help on this would be greatly appreicated, as I have a similiar question like this in my homework questions. Thanks in advance.
  2. jcsd
  3. Apr 3, 2009 #2
    Either the book is wrong or you have a typo, as the 3 should be a 2. The derivative is
    [tex]f'(x) = \frac{-2(x+1)}{(x-1)^2 \sqrt{x^2+1}}[/tex]

    It looks like you did the derivative correctly, except that the first 1/2 you encounter when reading your solution should be a 1. This comes from when you found the common denominator, and you will be able to further simplify the derivative after this change.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Finding derivative Date
How to find the derivative of this function Feb 13, 2018
Finding the min value using the derivative Feb 4, 2018
Find the derivative of this function Jan 12, 2018