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Need to find the equation

  1. Oct 30, 2005 #1
    Hello

    I have this problem that I cannot get part of. I need function f^(n)(x) for 1/(5x-1). I have been working it out and I know the denominator is going to be (5x-1) ^ (n+1) but can not figure out the top.

    So my question is how do I create a statment that evalutes the following

    when x = 1 it equal -5
    when x = 2 it equals -5 * -10 == 50
    when x = 3 it equals -5 * -10 * -15 == -750

    any hints would be great

    Thanks

    Peter
     
  2. jcsd
  3. Oct 30, 2005 #2

    benorin

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    Homework Helper

    Here's a hint

    Hint: as you differentiate, leave the coefficients factored. The answer your looking for involves a factorial and something else.
     
  4. Oct 30, 2005 #3
    Thanks. This is driving me crazy. I have been thinking is has to do with factorials all this time but not sure in what way.
     
  5. Oct 30, 2005 #4
    Please help

    Can anybody please help me I am stuck. Please please please
     
  6. Oct 30, 2005 #5
    Think I finally got it my answer -1^2(n!)5^n*(5x-1)^(-1-n)

    Thanks for your help
     
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