How to Calculate Partial Fraction Decomposition
What is Partial Fraction Decomposition?
Partial fraction decomposition breaks a complex rational expression into simpler fractions. It is essential for integration in calculus and for solving differential equations using Laplace transforms.
Formula
Express rational function as sum of simpler fractions: P(x)/Q(x) = A/(x−a) + B/(x−b) + ...
- P(x)
- numerator polynomial
- Q(x)
- denominator polynomial
- A, B, ...
- coefficients of partial fractions
Step-by-Step Guide
- 1For (ax+b)/((x+p)(x+q)): write as A/(x+p) + B/(x+q)
- 2Multiply both sides by denominator
- 3Equate coefficients or substitute values
- 4Solve for A and B
Worked Examples
Input
(3x+5)/((x+1)(x+2))
Result
A/(x+1) + B/(x+2); A=2, B=1
Input
1/(x²−1)
Result
1/((x−1)(x+1)) = ½/(x−1) − ½/(x+1)
Frequently Asked Questions
When is partial fractions useful?
Integration: ∫ P(x)/Q(x) dx becomes simpler. System solving and signal processing.
What if the numerator has degree ≥ denominator?
Use polynomial long division first. Then apply partial fractions to the remainder.
How do I handle repeated roots?
For root r repeated k times: include A/(x−r) + B/(x−r)² + ... + Z/(x−r)ᵏ.
Ready to calculate? Try the free Partial Fraction Decomposition Calculator
Try it yourself →