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!

Homework Help: Inverse laplace transofrm of natural logarithm

  1. May 8, 2010 #1
    1. The problem statement, all variables and given/known data

    the inverse laplace transform of [tex]ln\frac{s+2}{s-5}[/tex] using the inverse Laplace transform of the derivative

    2. Relevant equations

    [tex]L^{-1}[/tex]{[tex]\frac{d^{n}}{ds^{n}}F(S)[/tex]} = [tex](-1)^{n}t^{n}f(t)[/tex]

    3. The attempt at a solution

    the integral of [tex]ln\frac{s+2}{s-5}[/tex] I worked to be (s+2)ln(s+2)-(s+2) -(s-5)ln(s-5)+(s-5). So if this is F(S) then i still have no idea how to inverse it using the inverse Laplace transform of the derivative

    somehow i think im going down the wrong road... ?
    Last edited: May 8, 2010
  2. jcsd
  3. May 8, 2010 #2
    ok, i think i got it!

    i go the other way and make n = -1

    I have never seen this but just to clear this up: if [tex]\frac{d}{ds}}F(S)[/tex] is the derivative of F(S) then [tex]\frac{d^{-1}}{ds^{-1}}F(S)[/tex] is the same as the integration of F(S) right?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook