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!

Diff Eq problem, Laplace Transform

  1. Jun 20, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the Laplace Transform of the given function
    H(t-1)t^2

    I'm not sure how to add (t-1) to the t^2 term to solve the problem

    Any help would be greatly appreciated.
     
  2. jcsd
  3. Jun 20, 2009 #2
    That notation makes no sense, are you trying to translate the function on the s-axis? If you are what is the original function.
     
  4. Jun 20, 2009 #3
    If the original function is e^t*t^2 the translation = F(s-1) and since f(t)=t^2 its transform is 2/s^3, therefore you substitute s-1 in for s and get 2/(s-1)^3. Unless you are doing an inverse translation on the t-axis.
     
  5. Jun 21, 2009 #4
    My book states that it is a H(t) is a heavyside function and I'm suppose to use the proposition:

    L{H(t-c)f(t-c)}(s)=e^(-cs)F(s)
     
  6. Jul 14, 2009 #5
    Oh a unit step therefore you must translate both H(t) and F(t). LH(t-1)=e^s and f(t)=t^2, L(t^2)=2/s^3, so the transform is 2e^s/s^3
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook