How to find the inverse Laplace transform? I'm trying to calculate
$$\mathcal{L}^{-1}\left(\frac{3s^3-3s^2+3s-5}{s^2(s^2+2s+5)}\right)$$
But I am not sure how to go from here. I would be really grateful for any help. Thanks. 

Hint (@Amzoti's comment, rephrased): Start with $$\mathcal{L}^{-1}\left(\frac1s\right),\quad \mathcal{L}^{-1}\left(\frac1{s^2}\right),\quad \mathcal{L}^{-1}\left(\frac1{s+1+2\mathrm i}\right),\quad \mathcal{L}^{-1}\left(\frac1{s+1-2\mathrm i}\right).$$
