Laplace & Inverse Laplace Transforms

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Homework Help Overview

The discussion revolves around the Laplace and inverse Laplace transforms, specifically focusing on the expressions L[f(t)]= 1/(s^2+1)^2 + 1/(s^2+1) and L[f(t)]= ln(s+a), where 'a' is a constant. Participants are exploring how to handle the squared term in the first expression and the logarithmic function in the second.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the inverse Laplace transform of 1/(s^2+1) and express uncertainty about how to approach the squared form. There are inquiries about the inversion of logarithmic functions in the context of Laplace transforms, with one participant noting the lack of elementary functions corresponding to ln(s+a) as a Laplace transform.

Discussion Status

The discussion is ongoing, with participants sharing their attempts and expressing confusion about specific aspects of the problems. Some guidance has been offered regarding the use of Laplace transform tables, but no consensus has been reached on the best approach to the logarithmic function.

Contextual Notes

Participants are grappling with the implications of using squared terms and logarithmic functions in Laplace transforms, indicating potential gaps in their understanding or resources available for these specific cases.

2RIP
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Homework Statement


L[f(t)]= 1/(s^2+1)^2 + 1/(s^2+1)
L[f(t)]= ln(s+a) where 'a' is a constant

Homework Equations


The Attempt at a Solution


I know that the inverse laplace of 1/(s^2+1) is sin(t), but how do I deal with the squared form of it.

I have never encountered a logarithmic funcion for laplace, so can it be inverted back to f(t) with some of the common solution of conversion?

Thanks
 
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2RIP said:

Homework Statement


L[f(t)]= 1/(s^2+1)^2 + 1/(s^2+1)
L[f(t)]= ln(s+a) where 'a' is a constant


Homework Equations





The Attempt at a Solution


I know that the inverse laplace of 1/(s^2+1) is sin(t), but how do I deal with the squared form of it.

I have never encountered a logarithmic funcion for laplace, so can it be inverted back to f(t) with some of the common solution of conversion?

Thanks
For the first problem, and using a table of Laplace transforms, I see that:
L(1/(2w^2)(sin (wt) - wt cos(wt)) = 1/(s^2 + w^2)^2
and L(sin(wt)) = w/(s^2 + w^2)

I'm stumped on the other problem
 
No elementary function has ln(s+a) as its Laplace transform.
 
f(t) = (-t)^n[f(t)]
F(s) = F(s)^nth derivative

I believe that's what I got to do for the second one. thanks
 

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