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## Homework Statement

(4s^2+2)/(s^3+6s-20)

## The Attempt at a Solution

ok from an earlier question, i used partial frac, to re write it as (1/(s-2))+((3s+4)/(s^2+2s+10))

which i can re write to, by completing square to (1/(s-2))+((3s+4)/((s+1)^2+9))

now i think ive done all that ok.. so my inv laplace is:

e^(2t)+invlaplace((3s+4)/((s+1)^2+9))....

now im not completely sure on how to use s and t shifts properly(i just started this stuff today), and im quite unsure what to do from now but the answer should be

e^(2t)+(1/3)e^(-t)(9cos(3t)+sin(3t)) and i have no idea how to get that from that... what happens to the 4?? can anyone help plz