Partial Fraction Decomposition Calculator

Decompose rational functions into simpler partial fractions with step-by-step solutions

Enter Rational Function

Numerator Polynomial

Numerator: 5x^2 + 7

Denominator Polynomial

Denominator: x^3 - 2x^2 - 2x - 3

Rational Function

5x^2 + 7
x^3 - 2x^2 - 2x - 3

Partial Fraction Decomposition

4/x - 3 + x - 1/x² + x + 1
4
x - 3
x - 1
x² + x + 1

Step-by-Step Solution

1

Original rational function

f(x) = (5x^2 + 7) / (x^3 - 2x^2 - 2x - 3)
2

Factor the denominator

x^3 - 2x^2 - 2x - 3 = (x - 3)(x² + x + 1)
3

Set up partial fraction form

(5x^2 + 7)/((x - 3)(x² + x + 1)) = A/(x - 3) + (Bx + C)/(x² + x + 1)
4

Clear denominators and solve for coefficients

5x² + 7 = A(x² + x + 1) + (Bx + C)(x - 3)
5

Expand and collect like terms

5x² + 7 = (A + B)x² + (A - 3B + C)x + (A - 3C)
6

Compare coefficients

A + B = 5, A - 3B + C = 0, A - 3C = 7
7

Solve the system of equations

A = 4, B = 1, C = -1
8

Final partial fraction decomposition

(5x^2 + 7)/((x - 3)(x² + x + 1)) = 4/(x - 3) + (x - 1)/(x² + x + 1)

Quick Examples

Decomposition Rules

1

Linear Factors

For (ax + b): A/(ax + b)

2

Repeated Linear

For (ax + b)²: A/(ax + b) + B/(ax + b)²

3

Quadratic

For (ax² + bx + c): (Ax + B)/(ax² + bx + c)

4

Improper

If deg(numerator) ≥ deg(denominator), divide first

Solution Methods

Clear denominators by multiplying both sides

Expand and collect like terms

Compare coefficients of each power

Solve the resulting system of equations

Substitute back into partial fraction form

Understanding Partial Fraction Decomposition

What is Partial Fraction Decomposition?

Partial fraction decomposition is the process of breaking down a complex rational function (a quotient of polynomials) into a sum of simpler rational functions. This technique is particularly useful in calculus for integration, differential equations, and Laplace transforms.

Why Use Partial Fractions?

  • Simplifies integration of rational functions
  • Useful in solving differential equations
  • Essential for inverse Laplace transforms
  • Helps in analyzing systems and control theory

General Process

Step 1: Check Degree

If degree of numerator ≥ degree of denominator, perform polynomial long division first.

Step 2: Factor Denominator

Factor the denominator into irreducible linear and quadratic factors.

Step 3: Set Up Partial Fractions

Write the decomposition with unknown coefficients based on factor types.

Step 4: Solve for Coefficients

Clear denominators and solve the resulting system of equations.

Common Examples

Linear Factors

5x + 2 / (x - 1)(x + 3)
A/(x - 1) + B/(x + 3)

Repeated Linear Factor

3x - 5 / (x - 2)²(x + 1)
A/(x - 2) + B/(x - 2)² + C/(x + 1)

Quadratic Factor

x² + 1 / (x - 1)(x² + x + 1)
A/(x - 1) + (Bx + C)/(x² + x + 1)

Mixed Factors

2x³ + x + 1 / x²(x² + 4)
A/x + B/x² + (Cx + D)/(x² + 4)