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 transform

  1. Mar 23, 2012 #1
    1. The problem statement, all variables and given/known data

    Having found the laplace transform of a differential equation. I must now find X(t). All of my work is attached. The problem I am having is fitting my function of s to my table of transforms. I tried using partial fractions but it took me in a loop.

    3. The attempt at a solution

    I attached everything.

    Attached Files:

  2. jcsd
  3. Mar 23, 2012 #2
    I know the answer is et which means somehow 1/(s-1)2 becomes 1/(s-1). But I don't understand how to get rid of the other (s-1) in the denominator.
  4. Mar 24, 2012 #3
    Hey I still cant figure this one out. If anyone has any advice it would be very much appreciated. Thank you.
  5. Mar 24, 2012 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I have trouble reading your images, but if you are trying to inverse ##\frac 1 {(s-1)^2}## you can use one of the shifting theorems$$
    \mathcal L^{-1}f(s-a) = e^{at}\mathcal L^{-1}f(s)$$Do you see how to use that? Your answer isn't just ##e^t##.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook