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!

Maclaurin Series

  1. Dec 9, 2008 #1
    1. The problem statement, all variables and given/known data


    (1 pt) Compute the 9th derivative of:
    f(x) = [tex]\frac{cos(6x^4)-1}{x^7}[/tex]
    at x=0.



    2. Relevant equations

    Hint: Use the MacLaurin series for f(x).

    3. The attempt at a solution

    I have tried many weird ways and cannot come up with the correct numerical answer. I've gotten 0 each time and it still comes up as wrong. Please help point me in the correct direction, even if it is only a verbal explanation!

    Thanks so much
     
  2. jcsd
  3. Dec 9, 2008 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    The only term in the expansion that would contribute to a 9th derivative would be the term containing x^9. If you look up the Maclaurin series of cos you'll it can be written as a sum of even powers of it's argument. The fourth power of 6x^4 contains an x^16. 16-7=9. Is that enough of a hint.
     
  4. Dec 9, 2008 #3
    Yes, thank you very much. I think I can work it out now!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Maclaurin Series
  1. Maclaurin's Series (Replies: 1)

  2. Maclaurin Series (Replies: 16)

  3. Maclaurin series (Replies: 8)

  4. Maclaurin series (Replies: 5)

  5. Maclaurin series (Replies: 2)

Loading...