# Homework Help: Laplace Transform Problems

1. Nov 7, 2008

### tommyhakinen

1. The problem statement, all variables and given/known data
find the laplace transform of g(t) = t u(t-2) using the basic definition.

2. Relevant equations
L{f(t)} = ∫f(t)e-stdt from 0 to infinity

3. The attempt at a solution
I am able to get the transform by applying the t-shifting property. However, how do I do it by using basic definition? thanks.

2. Nov 7, 2008

### HallsofIvy

By integrating! Since H(x) is defined to be 0 for x< 0, 1 for x>= 0, H(t-2)= 0 for t< 2, 1 for t<= 2.
$$L{f(t)}= \int_2^\infty t e^{-st}dt$$
That should be easy.

3. Nov 7, 2008

### tommyhakinen

Thank you very much. One more question. what is the inverse laplace transform of 1? Is it possible to get it? if there is, what can be done? thanks..