I don't understand partial fraction decomposition

Click For Summary
SUMMARY

Partial fraction decomposition requires specific forms for the numerators based on the degree of the polynomial in the denominator. For a quadratic denominator like (x^2 + 3x + 6), the numerator must be linear, represented as Ax + B, to account for all possible terms. When the denominator is raised to a power, such as (x^2 + 3x + 6)^2, the decomposition includes terms like (Ax + B)/(x^2 + 3x + 6) and (Cx + D)/(x^2 + 3x + 6)^2 to ensure all polynomial degrees are represented. This structure is essential for accurately performing the decomposition and simplifying the expression.

PREREQUISITES
  • Understanding of polynomial functions and their degrees
  • Familiarity with the concept of rational functions
  • Basic knowledge of algebraic manipulation
  • Experience with solving equations involving fractions
NEXT STEPS
  • Study the derivation of partial fraction decomposition for rational functions
  • Learn about polynomial long division and its role in simplifying fractions
  • Explore examples of partial fraction decomposition with higher-degree polynomials
  • Practice solving partial fraction problems using software tools like Wolfram Alpha
USEFUL FOR

Students studying calculus, algebra, or anyone looking to deepen their understanding of rational functions and partial fraction decomposition techniques.

iScience
Messages
466
Reaction score
5
if there is something like (x^2+3x+6) in the denominator for one of the terms in a partial fraction problem, why do we put Ax+B instead of just A? and if the denominator is (x^2+3x+6)^2, why do we do {(Ax+B)/(x^2+3x+6)}+{(Cx+D)/(x^2+3x+6)^2}? i was always just told to memorize it, but why do we set it up this way? even a link to a derivation will probably help. the only thing i can find online is the formulas, basically what i just wrote.. but i want to know why those setups are the way they are, ie the reason behind them.
 
Physics news on Phys.org
Have you thought about the simplest cases? Suppose your initial fraction is just (4x- 2)/(x^2+ 3x+ 6). Do you think you ought to be able to write that as A/(x^2+ 3x+ 6)? What would have happened to the "4x"?
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
2
Views
2K