Partial Fraction Decomposition

In summary, the conversation discusses the need to convert an equation into a partial fraction decomposition in order to solve an inverse Laplace Transform. The equation in question is (-7s+52)/(s^2-8s+16) and the desired form is A/(s+a) + B/(s+a)^2. The individual has been struggling with the algebra and is seeking clarification on how to solve for A and B.
  • #1
PBJinx
10
0
The equation i currently have is

(-7s+52)/(s^2-8s+16)

I need to convert it into a partial fraction decomposition to do a inverse Laplace Transform, but i seem to be stuck with the algebra of the what I am supposed to do.


The equation I am supposed to use to set them is

A/(s+a) + B/(s+a)^2


What i have done so far is

S^2-8s+16=A/(s-4)+B/(s-4)^2

which then brings me to

A(s-4)^2+B(s-4)=7s+52

solving for A or B being 0 will not work. must I use quadratics to solve?

i am very lost and have been at this one all day
 
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  • #2
PBJinx said:
What i have done so far is

S^2-8s+16=A/(s-4)+B/(s-4)^2
I assume you mean this:
[tex]\frac{-7s+52}{s^2-8s+16} = \frac{A}{s-4} + \frac{B}{(s-4)^2}[/tex]

which then brings me to

A(s-4)^2+B(s-4)=7s+52
This is wrong. When you multiply both sides by s2 - 8s + 16 you should get
[tex]-7s + 52 = A(s - 4) + B[/tex]
 
  • #3
Ahh. thank you sir, got it right now
 

1. What is Partial Fraction Decomposition?

Partial Fraction Decomposition is a mathematical method used to break down a rational function into smaller, simpler fractions. It is often used in integration and solving differential equations.

2. Why is Partial Fraction Decomposition useful?

Partial Fraction Decomposition can make complex fractions easier to work with and can help in solving integration problems that would otherwise be difficult to solve. It can also help in finding the roots of a polynomial function.

3. How do you perform Partial Fraction Decomposition?

To perform Partial Fraction Decomposition, the rational function is first factored into linear and irreducible quadratic factors. Then, the coefficients of each factor are determined by setting up a system of equations and solving for the unknown coefficients.

4. What are the different types of Partial Fraction Decomposition?

The two main types of Partial Fraction Decomposition are proper and improper. Proper decomposition is used when the degree of the numerator is less than the degree of the denominator, while improper decomposition is used when the degree of the numerator is greater than or equal to the degree of the denominator.

5. When is Partial Fraction Decomposition not possible or necessary?

Partial Fraction Decomposition is not possible if the denominator of the rational function cannot be factored into linear and irreducible quadratic factors. It is also not necessary if the goal is to simply evaluate the function, as it can be done directly without decomposing it.

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