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: Where to start with laplace

  1. Dec 26, 2005 #1
    for the following question:
    let f(t)=t^2. derive L(f) from L(1)

    my problem:
    i have no clue where to start...
  2. jcsd
  3. Dec 26, 2005 #2
    You need to apply the "frequency division" rule :

    [tex]{ \cal L} \{ tf(t) \} = (-1) F^{'}(s)[/tex]

    [tex]{ \cal L} \{ t^nf(t) \} = (-1)^n F^{(n)}(s)[/tex]


    [tex]{ \cal L} \{ f(t) \} = F(s)[/tex]

    and in this case

    [tex]f(t) = 1[/tex]


    edit : all rules can be found here
    Last edited: Dec 26, 2005
  4. Dec 28, 2005 #3
    wow!!! thank you very much!!!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook