Calculus

Integration of Functions

Integration of Functions Logo

Partial Fraction Decomposition

Solved Problems

Example 7.

Determine a partial fraction decomposition for the function

Solution.

The partial fraction decomposition has the form

We combine the partial fractions on the right side into a single fraction and then equate the numerators on both sides. This yields:

Hence we obtain the following system of equations:

Solving it, we find the unknown coefficients:

The partial fraction decomposition is given by

Example 8.

Determine a partial fraction decomposition for the function

Solution.

First we factor the cubic function in the denominator:

As the denominator contains only linear factors, the decomposition has the form

Combining the partial fractions on the right side into a single fraction and equating the numerators on both sides, we have:

The system of equations for the unknown coefficients is written as

It has the following solution:

so the decomposition of the original rational function is expressed by the equation:

Example 9.

Decompose using the partial fractions.

Solution.

Given the irreducible quadratic factor in the denominator, we write the partial fraction expansion in the form

The equation for the unknown coefficients is given by

or

We obtain the system of equations:

This yields:

Hence, the partial fraction decomposition is written as

Example 10.

Expand the rational function into partial fractions.

Solution.

Note that the denominator contains the irreducible quadratic factor and the linear factor with multiplicity Hence, the partial fraction decomposition is written as

To determine the unknown coefficients we clear fractions multiplying both sides by the denominator. This gives

By equating coefficients of similar powers on both sides, we have

We solve the resulting system and find

Hence, the partial fraction decomposition of the rational function is given by

Example 11.

Decompose using the partial fractions.

Solution.

The denominator has the irreducible quadratic factor Hence, the partial fraction decomposition has the form

By equating the numerators on both sides of the equation, we have

We get the following system of equations:

It has the solution

Hence, the partial fraction decomposition is given by

Page 1 Page 2