# whats the laplase transformation of this one..

• Aug 17th 2009, 01:31 PM
transgalactic
whats the laplase transformation of this one..
$
\frac{-2e^{-s}}{s^3}
$

i know that e ill make u function
but i dont know the rest
• Aug 17th 2009, 01:53 PM
Chris L T521
Quote:

Originally Posted by transgalactic
$
\frac{-2e^{-s}}{s^3}
$

i know that e ill make u function
but i dont know the rest

Recall that $\mathcal{L}^{-1}\left\{e^{-as}F\left(s\right)\right\}=u\left(t-a\right)f\left(t-a\right)$

So here, we see that $-2e^{-s}{s^3}=-e^{-s}\frac{2!}{s^3}$

Therefore, $\mathcal{L}^{-1}\left\{-e^{-s}\frac{2!}{s^3}\right\}=-u\left(t-1\right)\cdot\left(t-1\right)^2$