# Homework Help: What's the inverse Laplace transform of this?

1. Jan 8, 2012

1. The problem statement, all variables and given/known data

$$L^{-1}\{\frac{1}{(s^2+4)^2}\}$$

2. Relevant equations

3. The attempt at a solution
I have no idea how to solve this. Any idea to being solving the problem would be appreciated.

2. Jan 8, 2012

### gomunkul51

One way so solve it (propably not the simplest but an interesting one) would be to use the fact that F(s)G(s) (multiplication of the functions) in Laplace plane is f(t)*g(t) (convolution of the functions) in "time" plane.

$$L^{-1}\left \{ \frac{1}{(s^2+4)^{2}} \right \} = L^{-1}\left \{ \frac{1}{(s^2+4)} \right \}*L^{-1}\left \{ \frac{1}{(s^2+4)} \right \}$$

ROM.