Partial Fractions: Expanding & Laplace Transforms

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Homework Help Overview

The discussion revolves around the topic of partial fractions and their application in Laplace transforms, specifically focusing on the expression (2s+1)/((s-1)^2 + 1). Participants are exploring how to express this in a suitable form for Laplace transforms.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants are attempting to understand the partial fraction decomposition of the given expression and how it relates to Laplace transforms. Some are questioning the appropriateness of the forum for this topic, while others are discussing the nature of the denominator and its irreducible quadratic factor.

Discussion Status

There is an ongoing exploration of how to manipulate the expression for Laplace transforms, with some participants providing insights into the structure of the expression and its components. However, there is no explicit consensus on the best approach or method to take.

Contextual Notes

One participant notes that the expression involves an irreducible quadratic factor in the denominator, which may limit the use of real numbers in the decomposition. Additionally, there is mention of the potential misplacement of the thread in the forum.

mxpxer7
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I'm sure this is a no brainer to someone, but here it is..

what is does the partial fraction of this look like in expanded form? Or how can I make it fit on the table of laplace transforms?

__(2s+1)__
(s-1)^2 + 1
 
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I think you'd get more replies (and better ones) if you posted this in the algebra forum, as this doesn't really have anything to do with differential equations. Your case would fall under the "irreducible quadratic factor in the denominator", as the denominator has zeroes s=1+i and s=1-i which aren't real:

http://en.wikipedia.org/wiki/Partial_fraction#An_irreducible_quadratic_factor_in_the_denominator

So what you wrote is the simplest form if you want to use only real numbers.
 
I apologize for putting this in the wrong section I'm using the answer for la place transforms so maybe this is where the calculus comes in, How can i write this so it fits into the table of laplace transforms?
 
F(s)=\frac{2s+1}{(s-1)^2+1}=2\frac{s-1}{(s-1)^2+1}+3\frac{1}{(s-1)^2+1}=G(s-1)

where G(s)=2\frac{s}{(s)^2+1}+3\frac{1}{(s)^2+1}

The inverse Laplace transform of G(s) is 2*cos(x)+3*sin(x). The inverse Laplace transform of G(s-1) is e^x[2*cos(x)+3*sin(x)] according to some of the properties of Laplace transforms and a shifted arguments.
 
RedX said:
F(s)=\frac{2s+1}{(s-1)^2+1}=2\frac{s-1}{(s-1)^2+1}+3\frac{1}{(s-1)^2+1}=G(s-1)

where G(s)=2\frac{s}{(s)^2+1}+3\frac{1}{(s)^2+1}

The inverse Laplace transform of G(s) is 2*cos(x)+3*sin(x). The inverse Laplace transform of G(s-1) is e^x[2*cos(x)+3*sin(x)] according to some of the properties of Laplace transforms and a shifted arguments.

Nice shortcut...
 

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