Partial Fractions - Resolving a given rational function into partial fractions

  • Partial fractions is a technique used to decompose a rational function into simpler fractions.
  • The rational function is a fraction where the numerator and the denominator are both polynomials.
  • The partial fraction decomposition involves breaking the rational function into a sum of simpler fractions with denominators that are linear factors or irreducible quadratic factors.
  • The technique involves finding the unknown coefficients in the partial fraction expression by equating the numerator of the rational function to the sum of the numerators of the partial fractions.
  • Partial fraction decomposition is used in integration of rational functions, solving differential equations, and signal processing.

Resolving a given rational function into partial fractions:

  • To resolve a given rational function into partial fractions, first factorize the denominator of the rational function into linear or irreducible quadratic factors.
  • Express the partial fraction decomposition in the form of unknown coefficients over linear or irreducible quadratic factors.
  • Equate the numerator of the rational function to the sum of the numerators of the partial fractions, and solve for the unknown coefficients using algebraic methods.
  • If there are repeated factors in the denominator, then use the denominators raised to increasing powers as denominators in the partial fraction decomposition.
  • If the degree of the numerator is greater than or equal to the degree of the denominator, then perform long division to obtain a proper fraction, and then resolve the proper fraction into partial fractions.

Important Formulas to Remember in these Partial Fractions


Partial Fractions:

  • Let $R(x)$ and $Q(x)$ be two polynomials such that $deg(R(x)) < deg(Q(x))$. Then $R(x)/Q(x)$ can be expressed as a sum of partial fractions of the form: $$\\frac{A}{x-a} + \\frac{B}{(x-a)^2} + \\cdots + \\frac{L}{(x-a)^k} + \\frac{R(x)}{Q(x)}$$ where $a$ is a root of $Q(x)$ of multiplicity $k$ and $A, B, \\ldots, L$ are constants.

Resolving a Given Rational Function into Partial Fractions:

  • Let $R(x)$ and $Q(x)$ be two polynomials such that $deg(R(x)) < deg(Q(x))$. Then $R(x)/Q(x)$ can be expressed as a sum of partial fractions by following the steps given in the algorithm.