Partial Fraction Question: HELP with Polynomial Long Division

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Homework Help Overview

The discussion revolves around the problem of decomposing the rational expression (x^2 - x - 13)/((x^2 + 7)(x - 2)). Participants are exploring the necessary steps for partial fraction decomposition, including the potential need for polynomial long division.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the requirement of polynomial long division and question whether it is necessary given the degrees of the numerator and denominator. There is also a focus on how to properly express the rational expression in terms of partial fractions.

Discussion Status

The discussion is ongoing, with participants offering differing opinions on the necessity of polynomial long division. Some guidance has been provided regarding the structure of partial fractions, but there is no explicit consensus on the approach to take.

Contextual Notes

There is a noted concern about the clarity of the expression due to potential misinterpretation of the original problem statement. Participants are also reflecting on the importance of showing work to support their answers.

n31son
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Homework Statement



x^2-x-13/(x^2+7)(x-2)

hello i am having trouble solving this problem.. could anyone please show me how to do this step by step? i know polynomial long division is required before it can be converted to partial fractions.

I also know the answer is 2x+3/x^2+7 - 1/x-2 from an online calculator. but think I am missing something in the method to reach the answer.
any help appreciated thanks
 
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n31son said:

Homework Statement



x^2-x-13/(x^2+7)(x-2)
Unless you meant x2 - x - (13/(x2 + 7)(x - 2)), this should be written as (x^2-x-13)/((x^2+7)(x-2)).


n31son said:
hello i am having trouble solving this problem.. could anyone please show me how to do this step by step? i know polynomial long division is required before it can be converted to partial fractions.

I also know the answer is 2x+3/x^2+7 - 1/x-2 from an online calculator. but think I am missing something in the method to reach the answer.
I doubt that is the answer. Maybe you meant (2x + 3)/(x2 + 7) - 1/(x - 2). You should get in the habit of using parentheses around the numerator and denominator of your fractions.
n31son said:
any help appreciated thanks

No, you don't need to do polynomial long division first. The degree of the numerator is less than the degree of the denominator, so that division is unnecessary.

How did you break up the two fractions?
 


its defo the answer as it has been marked but returned for not showing working.
i may be wrong about the poly long division tho.
 


pf qu.jpg
 


What you show in post #4 is what you're starting with. When you decompose a rational expression such as that, you write it as a sum of two or more rational expressions.

For example, if you had to decompose x/(x2 - 4), you would write it as A/(x - 2) + B/(x + 2), and you would solve for the constants A and B.

How are you going to break up your rational expression?
 

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