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. Oct 10, 2012 #1
    1. The problem statement, all variables and given/known data
    f(t) is a piecewise function:
    {0 0<= t< 1
    {t*exp(2t) t = >1


    2. Relevant equations
    F(s)= L{f(t)}


    3. The attempt at a solution

    F(s)= L{t*exp(2t)}

    for this problem I just took the Laplace Transformer directly from the table which is: n!/ (s-a)^(n+1)

    and after plucking in the relevant number I got:
    1/(s-2)^2

    Firstly I want to ask, is this correct? And have I missed any steps when setting up this problem?

    Secondly if this is correct and I don't want to use the table to get the formula directly, can someone please show me other methods to come to the same answer.

    thanks,
    Phil
     
  2. jcsd
  3. Oct 11, 2012 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    What you have is incorrect. That is the Laplace transform of [itex]f(t)= te^{2t}[/itex] which is NOT the same as the function given here.

    Do not know the definition of the Laplace transform? It is
    [tex]F(f)= \int_0^\infty e^{-st}f(t)dt[/tex]

    Integrate that.
    The Laplace transform of this function is
    [tex]\int_1^\infty e^{-st}te^{2t}dt= \int_1^\infty te^{(2- s)t}dt[/tex]
     
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)

Loading...