# Math Help - Laplace transforms (shift thereom)

1. ## Laplace transforms (shift thereom)

Can someone tell me if the asnwer to

Using the first shift thereom, determine
$L^{-1} { \frac {s}{s^2 + 4s+ 20}}$

Is $e^{-2t} cos4t - 0.5e^{-2t} sin4t$

Cheers!

2. Originally Posted by mongmong
Can someone tell me if the asnwer to

Using the first shift thereom, determine
$L^{-1} { \frac {s}{s^2 + 4s+ 20}}$

Is $e^{-2t} cos4t - 0.5e^{-2t} sin4t$

Cheers!
Since the expresion can be written as $\frac{s + 2}{(s + 2)^2 + 4^2} - \frac{2}{(s + 2)^2 + 4^2}$, your answer is correct.