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Simplifying and Integrating a Rational Function by Completing the Square

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Simplify and integrate 4x22x8dx\displaystyle \int \frac{4}{x^2 - 2x - 8} \, dx by completing the square.

This problem deals with the integration of a rational function, which can often present complexities that require several strategic algebraic manipulations to resolve. A common approach to these problems involves rewriting the given expression in a form that is easier to integrate, which in this case refers to completing the square. Completing the square is a technique used to convert a quadratic expression into a perfect square trinomial, aiding in simplifying the integral. This transformation is instrumental in integration, especially when dealing with rational functions where the denominator includes a quadratic expression.

Once the polynomial is expressed as a perfect square, the integration can proceed using a simple substitution or by recognizing the integral as a standard form. This method is particularly useful when combined with other techniques such as partial fraction decomposition or trigonometric substitution, though in this instance, completing the square sets up the problem for evaluation by standard substitution techniques.

Understanding this approach not only helps in solving this specific problem more efficiently but serves as a potential strategy for a variety of related integrals. By practicing this method, students solidify their algebra skills while developing a deeper intuition for the integration process, ultimately broadening their toolkit of techniques for tackling diverse integration problems.

Posted by Gregory 5 months ago

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