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OpenStudy (anonymous):

Laplace Transforms Question

OpenStudy (anonymous):

\[\mathcal L (1*t^3)\] evaluate

OpenStudy (dominusscholae):

Formula for \[L({t^n}) = {n!}/s^{n+1}\]

OpenStudy (anonymous):

that isn't multiplaction it's like a dot product

OpenStudy (anonymous):

special instance

OpenStudy (anonymous):

\[\mathcal L(1*t^3)=\mathcal L (1) \mathcal L (t^3)\]

OpenStudy (dominusscholae):

Oh a convolution......hmmm. gimme a sec.

OpenStudy (anonymous):

\[\mathcal L(1*t^3)=\mathcal L (1) \mathcal L (t^3)\] This will be a normal multiplication @Outkast3r09 Right ??

OpenStudy (dominusscholae):

No it wouldn't. Laplace transforms don't work like that last time I checked.

OpenStudy (anonymous):

I mean to say that if we find L(1) and L(t^3) Then we will multiply it simply ??

OpenStudy (anonymous):

use this \[\Large L(t^nf(t)=(-1)^n*\frac{d^n}{ds^n}(F(s))\] where f(t)=1 so F(s)=1/s

OpenStudy (anonymous):

\[\mathcal {L}(1) = \int\limits _{0}^{\infty}(1)(e^{-st}) dt \implies \left| -\frac{e^{-st}}{s} \right|_0^{\infty} \implies \frac{1}{s}\]

OpenStudy (anonymous):

also Laplace is Linear operator so \[\Large L(A.B)\neq L(a)*L(b)\]

OpenStudy (anonymous):

\[\large \mathcal {L} (t^n) = \frac{n!}{s^{n+1}}\]

OpenStudy (anonymous):

\[\mathcal{L} \{f(t)*g(t)\}=\mathcal{L}\{f(t)\}\mathcal{L}\{g(t)\}\]You silly geese! "*" represents convolution!!

OpenStudy (anonymous):

which = \[F(s)G(s)\]

OpenStudy (anonymous):

so multiplication of the two transforms

OpenStudy (anonymous):

\[\mathcal L (1*t^3)=\mathcal L(1) \mathcal L (t^3)=\frac{1}{s}*\frac{6}{s^4}=\frac{6}{s^5}\]

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