Express in partial fractions \(\frac{x-\gamma}{(x-\alpha)(x-\beta)} .\)

When we talk about algebraic fractions, we refer to fractions where the numerator and denominator contain algebraic expressions, often including variables like x, coefficients, and sometimes constants. Just as we simplify numerical fractions by breaking them down into simpler parts, algebraic fractions can be deconstructed into partial fractions, making them more manageable to work with, especially when it comes to integration or finding limits in calculus.

For example, considering the fraction \( \frac{x-\gamma}{(x-\alpha)(x-\beta)} \) where \(\alpha\), \(\beta\), and \(\gamma\) are constants, we can decompose it into a sum of simpler fractions where the denominators are the factors of the original denominator. This process is known as partial fractions decomposition. It's akin to breaking a complex problem into easier-to-handle pieces, enabling a step-by-step approach to find the solution.

Rational expressions are fractions that involve polynomials in both the numerator and the denominator. They can be as straightforward as \(\frac{x}{x+1}\) or as complicated as \(\frac{x^2 + 2x + 1}{x^3 - 6x^2 + 11x - 6}\). The idea is to represent quantities that are not whole numbers and can vary depending on the value of the variable.

To simplify these expressions, we often aim to factor polynomials, cancel common factors, and use other algebraic manipulations, such as the polynomial long division or partial fractions decomposition. These simplified forms are crucial for carrying out higher-level calculus operations, like integration, more effectively. In the case of partial fractions, this simplification can be visualized as separating a complex expression into a sum of simpler ones, each with its own variable parts distinguishable and straightforward to integrate or differentiate.

Just as in arithmetic, where we divide numbers using long division, polynomial long division is a technique used to divide polynomials which are too complicated to be factored easily. The process involves dividing the highest degree term of the numerator by the highest degree term of the denominator and then subtracting the result from the numerator until a remainder is found that cannot be further divided by the denominator.

This method might be used prior to partial fraction decomposition if the degree of the numerator is greater than or equal to the degree of the denominator, in such cases, we must first use polynomial long division to simplify the expression.

Benefits of Polynomial Long Division

• Reduces a complex rational expression into a simpler form.
• Allows us to write improper fractions as a polynomial plus a proper fraction.
• Facilitates further algebraic manipulations, making it easier to find solutions.
• Prepares an expression for other techniques, like partial fractions decomposition, when appropriate.