(New page: == '''Fundamentals of Laplace Transform''' == Let the signal be: <math>x(t) =e^ {-at} \mathit{u} (t).</math> Here is how to compu...)
 
 
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</math>
 
</math>
 
Note: the last equality (with a *) is untrue. Please do not write this on the test or you will get points marked off. I really appreciate this mistake being on Rhea, please do not erase it --[[User:Mboutin|Mboutin]] 11:58, 21 November 2008 (UTC)
 
Note: the last equality (with a *) is untrue. Please do not write this on the test or you will get points marked off. I really appreciate this mistake being on Rhea, please do not erase it --[[User:Mboutin|Mboutin]] 11:58, 21 November 2008 (UTC)
 
Correction of above:
 
 
<math>
 
\begin{align}
 
X(s) &= \int_{-\infty}^{\infty}x(t){e^{-st}}\, dt, \\
 
    &= \int_{0}^{\infty}{e^{-at}}{e^{-st}}dt  ,\text{ let  } s=b+j\omega,  \\
 
    &=\int_{0}^{\infty}{e^{-(a+b+j\omega)t}}dt,  \\
 
\end{align}
 
</math>
 
 
If <math>a+b\leq 0</math>, then the integral Diverges
 
 
Else,
 
 
<math>
 
\begin{align}
 
X(s) &=\frac{e^{-(a+b)t}e^{-j\omega t}}{-(a+b+j\omega)}|_0^\infty, \\
 
    &=0-\frac{-1}{s+a},  \\
 
    &=\frac{1}{s+a}
 
\end{align}
 
</math>
 
 
~ Ananya Panja
 

Latest revision as of 11:19, 24 November 2008


                       == Fundamentals of Laplace Transform ==
     Let the signal be:
     $ x(t) =e^ {-at} \mathit{u} (t). $
     
     Here is how to compute the Laplace Transform of $ x(t) $:
     $  \begin{align} X(s) &= \int_{-\infty}^{\infty}x(t){e^{-st}}\, dt, \\      &= \int_{-\infty}^{\infty}{e^{-at}}{e^{-st}}dt   ,\text{ since }\mathit{u} (t)=1,\text{ for }t>0, \text{ else }\mathit{u} (t)=0, \\      &=\frac{1}{s+a}. ~^*  \end{align}  $

Note: the last equality (with a *) is untrue. Please do not write this on the test or you will get points marked off. I really appreciate this mistake being on Rhea, please do not erase it --Mboutin 11:58, 21 November 2008 (UTC)

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Ph.D. on Applied Mathematics in Aug 2007. Involved on applications of image super-resolution to electron microscopy

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