Evaluating the Integral of x^2 / ((x^4+x^2+1)(ax^2+1))

Published on August 11, 2026

Calculus

Learn how to evaluate the complex rational integral using partial fraction decomposition and algebraic substitution techniques.

Question

integral ((x^2/(x^4+x^2+1)(ax^2+1))

Answer

To evaluate the integral
we can use a substitution method by manipulating the integrand to create a form suitable for integration.

Step 1: Algebraic Manipulation

First, let’s divide the numerator and denominator by :
Notice that . Let . Then . However, the term makes this direct substitution difficult.
Instead, let’s use partial fraction decomposition on the term .
Let . We are looking for a decomposition of the form:
Multiplying through by the denominator:
Equating coefficients of :
Substitute into the second equation:
Then:

Step 2: Rewriting the Integral

The integral becomes:
Let .
Part A:
Part B:
Perform polynomial division: (Wait, let’s re-divide):
So, .

Step 3: Combining and Simplifying

Notice that the from Part B cancels the from Part A.
To solve , divide by :
This is generally solved by splitting the numerator into and .
Let .
The remaining part is solved by .
Final Answer Form: