1. The problem statement, all variables and given/known data I have three inverse laplace transforms I can't solve, they are, i) (s-1)/(s^2 + 8s + 17) ii) (s+3)/(s^2 + 4s) iii) 2/[(s+1)*(s^2 + 1)] 2. Relevant equations The laplace transform table, http://en.wikipedia.org/wiki/Laplace_transform#Table_of_selected_Laplace_transforms 3. The attempt at a solution i) I completed the square and got, (s-1)/(s^2 + 8s + 17) -->(s-1)/[(s+4)^2 -1] then split up into, s/[(s+4)^2 -1] and -1/[(s+4)^2 -1] my answer was e^-4t *cos(t) - e^-4t *sin(t) but the answer is e^-4t *cos(t) - 5e^-4t *sin(t) , I do not know where the 5 has come from ? ii) I'm not sure where to start on this one (s+3)/(s^2 + 4s) , I have taken out a factor of 1/s but im not sure were to go from there. iii) For this one, I'm not having problem with the actual laplace but rather partial fractions, what I have done, 2/[(s+1)*(s^2 + 1)] = A/(s+1) + B/(s^2 + 1) A(s^2 + 1) + B(s+1) = 2 for s=-1 I found A= 1 but I'm stuck at finding B, how do I make (s^2 + 1) = 0 Thanks a lot in advance !