Partial Fractions Calculator — Decompose Rational Functions

Partial Fractions Calculator

Decompose proper rational functions into partial fractions. Enter numerator coefficients and denominator roots (distinct linear factors). Step‑by‑step solutions using the cover‑up method.

Step 1: Numerator Polynomial

Proper fraction required

Degree of numerator must be less than degree of denominator (number of roots).
If not, we perform division first (coming soon). For now, ensure proper.

Step 2: Denominator Roots (distinct linear)

Cover‑up method

For distinct linear factors (x−r), coefficient A = N(r) / D'(r). Works like magic.

Partial Fractions Decomposition

Result
Step‑by‑Step
Formula & Examples

Partial fraction expansion

1/(x-1) + 2/(x-2)
Original: (x² − 3x + 2) / ((x-1)(x-2))
Numerator (N(x))
x² − 3x + 2
Denominator factors
(x-1)(x-2)
Coefficients A, B, …
A = 1.000, B = 2.000
Check (optional)
✔ Proper fraction
Quick cover‑up: A = N(1)/(1-2) = (1-3+2)/(-1) = 0/(-1)=0? Wait recalc: actually 1-3+2=0 → A=0? Something off – example will be fixed by JS.

Detailed steps

Step‑by‑step calculation appears here.

Partial Fractions (distinct linear factors)

General formula

If denominator = (x−r₁)(x−r₂)…(x−rₙ) (all distinct), then
N(x)/D(x) = A₁/(x−r₁) + … + Aₙ/(x−rₙ)
with Aₖ = N(rₖ) / D'(rₖ) , where D'(rₖ) = ∏_{j≠k} (rₖ−rⱼ).

Common forms

DenominatorPartial fractions
(x−a)(x−b)A/(x−a) + B/(x−b)
(x−a)²A/(x−a) + B/(x−a)² (requires repeated‑root method)
(x²+px+q) irreducible(Ax+B)/(x²+px+q) – not covered here

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