Inverse Laplace Transform: How to Manipulate Fractions for Completing the Square

In summary, the inverse Laplace transform of the given function is not directly applicable to the known Laplace transform equations. It requires further manipulation to fit the cosine equation and make use of the shifting theorems.
  • #1
TyErd
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Homework Statement


Find the inverse laplace transform of [itex]\frac{3s + 7}{s^{2} - 2s + 10}[/itex]

Homework Equations


completing the square.
[itex]e^{at}sin(bt) = \frac{b}{(s-a)^{2} + b^{2}}[/itex]
[itex]e^{at}cos(bt) = \frac{s-a}{(s-a)^{2} + b^{2}}[/itex]

The Attempt at a Solution


F(s)= [itex]\frac{3s + 7}{s^{2} - 2s + 10}[/itex]
F(s) = [itex]\frac{3s + 7}{(s-1)^{2} +9}[/itex]
F(s) = [itex]\frac{3s}{(s-1)^{2} +9} + \frac{7}{(s-1)^{2} +9} [/itex]

after this i don't know how to manipulate the first fraction to fit the cosine equation. I know the 3 can be taken up front and a=1 and b=3 I am pretty sure when comparing with the cosine equation but there the problem of making s into s-1.
 
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  • #2
Don't you have the shifting theorems? Like$$
\mathcal L e^{at}f(t) = \mathcal L(f(t))|_{s \to s-a}$$
 

FAQ: Inverse Laplace Transform: How to Manipulate Fractions for Completing the Square

What is the Inverse Laplace Transform?

The Inverse Laplace Transform is a mathematical operation that takes a function in the frequency domain and converts it back into the time domain. It is the inverse of the Laplace Transform, which converts a function from the time domain to the frequency domain.

Why is the Inverse Laplace Transform important?

The Inverse Laplace Transform is important because it allows us to solve differential equations in the frequency domain, which can be easier and more efficient than solving them in the time domain. It also has many applications in various fields of science and engineering.

How is the Inverse Laplace Transform calculated?

The Inverse Laplace Transform is calculated using a variety of methods, such as partial fraction decomposition, contour integration, and the use of tables and properties of Laplace Transforms. The method used depends on the complexity of the function and the desired accuracy of the result.

What are some common applications of the Inverse Laplace Transform?

The Inverse Laplace Transform has many applications in science and engineering, including solving systems of differential equations, analyzing electrical circuits, and studying the behavior of physical systems. It is also used in signal processing, control theory, and image processing.

Are there any limitations to using the Inverse Laplace Transform?

One limitation of the Inverse Laplace Transform is that it can only be applied to functions that have a Laplace Transform in the first place. It also does not work for functions with complex singularities or for functions that do not have a finite Laplace Transform. Additionally, the calculation of the Inverse Laplace Transform can be complex and time-consuming for certain functions.

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