Integrate the functions`1/((x^2+1)(x^2+4)`

Explanation

To solve the integral \( \int \frac{1}{(x^2 + 1)(x^2 + 4)} \, dx \), we will use the method of partial fractions. Let's go through the solution step by step.

### Step 1: Set up the partial fractions
We want to express the integrand as a sum of simpler fractions. We can write:

\[ \frac{1}{(x^2 + 1)(x^2 + 4)} = \frac{A}{x^2 + 1} + \frac{B}{x^2 + 4} \]
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