Partial Fraction Question: HELP with Polynomial Long Division

In summary: You need to decompose it into a sum of two or more rational expressions. For x/(x2 - 4), you would write it as A/(x - 2) + B/(x + 2), and then solve for the constants A and B.
  • #1
n31son
3
0

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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  • #2


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?
 
  • #3


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.
 
  • #4


pf qu.jpg
 
  • #5


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?
 

Related to Partial Fraction Question: HELP with Polynomial Long Division

1. What is partial fraction decomposition?

Partial fraction decomposition is a method used in mathematics to decompose a rational function into simpler fractions. It involves breaking down a complex fraction into smaller, easier-to-solve fractions.

2. When is partial fraction decomposition used?

Partial fraction decomposition is commonly used in calculus, algebra, and engineering to simplify integrals, solve equations, and perform other mathematical operations involving rational functions.

3. How do you perform polynomial long division?

Polynomial long division is a method used to divide polynomials. It involves dividing the numerator polynomial by the denominator polynomial, similar to long division with whole numbers. The result is a quotient and a remainder.

4. How do you use polynomial long division to help with partial fraction decomposition?

Polynomial long division is used to determine the coefficients of the simpler fractions that make up the original rational function. These coefficients are then used to write the partial fraction decomposition.

5. What are some common mistakes to avoid when using polynomial long division for partial fraction decomposition?

Some common mistakes to avoid include not properly factoring the denominator polynomial, not aligning the terms correctly during the division process, and forgetting to include all the necessary terms in the final decomposition. It is important to double check your work and be careful with the calculations.

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