1. Not finding help here? Sign up for a free 30min 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!

L'hopitals Derivative

  1. Apr 23, 2008 #1
    [SOLVED] L'hopitals Derivative

    1. The problem statement, all variables and given/known data

    lim x->0 [tex] \frac{1-x^2-e^{-x^2}}{x^4}[/tex]


    I ended up using l'hopitals rule 4 times before I got the answer. And I got an answer of -1/2. I was wondering if someone could check that to see if its right. I would post all my work but that would take a while, however, if you want to see more of my steps ill be glad to do so. I tried graphing it on my calculator, but depending where I put the parenthesis it was right or wrong. Thanks
     
  2. jcsd
  3. Apr 23, 2008 #2
    My final equation looked like so...

    [tex] \frac{16x^4e^{-x^2} - 24x^2e^{-x^2} + 16x^2e^{-x^2} - 8e^{-x^2} + 8x^2e^{-x^2} - 4e^{-x^2}}{24}[/tex]
     
  4. Apr 23, 2008 #3
    You can start by replacing x^2 with y in the beginning for nicer equations. I have not been doing anything with l'hopital yet, but I used the infinite series of e^x and got the same answer as you.
     
  5. Apr 23, 2008 #4
    Ok, I have another question. The derivative of [tex]-e^{-x^2}[/tex] would be [tex]2xe^{-x^2}[/tex] is that correct?
     
  6. Apr 23, 2008 #5
    i just replaced it with y and that was much easier thanks
     
  7. Apr 23, 2008 #6

    exk

    User Avatar

    yes the derivative is correct as is your solution.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: L'hopitals Derivative
  1. L'Hopital's Rule? (Replies: 6)

  2. Limits and L'Hopital (Replies: 21)

Loading...