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!

Laplace transform

  1. May 14, 2009 #1
    I need to find the laplace transform of
    y''(t)-y(t)=0 with initial conditions y(0)=1 and y'(0)=3

    My attempt:
    so (s^2)F(s)-s(1)-(3)-sF(s)-1=0
    I need to isolate F(s) so
    Is this correct?
  2. jcsd
  3. May 14, 2009 #2


    User Avatar
    Homework Helper

    You're solving for a different differential equation than the one you have listed. You are solving [itex]y''(t)-y'(t)=0[/itex]. That said you still made some mistakes. Your first two steps are correct, but then when you subtract the two you make a minus sign error. It should be,

    [tex]s^2 F(s)-s-3-(s F(s)-1)=s^2 F(s)-s-3-sF(s) \textcolor{red}{+} 1=0[/tex].

    I am not sure how you isolated the F(s), something seems to have gone wrong there as well. You can write it like,

  4. May 14, 2009 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    You wrote the problem as y"- y= 0, but you solved y"- y'= 0.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Laplace transform
  1. Laplace Transformation (Replies: 5)

  2. Laplace Transform (Replies: 1)

  3. Laplace Transforms (Replies: 4)

  4. Laplace transformation (Replies: 2)

  5. Laplace transform (Replies: 3)