Help with integration, involving integration by partial fractions.

In summary, the problem is to integrate (3x^2-4)/(x^3-4x-6) using integration by parts, but the student is unsure of how to set it up. They attempted to use a perfect squares situation, but it did not work. Another student suggests trying a u substitution and the original student realizes their mistake. The conversation ends with a reminder to consider substitution as a first technique.
  • #1
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Homework Statement



(3x^2-4)/(x^3-4x-6)

Homework Equations



I guess integration by parts... But how do i set this up?

The Attempt at a Solution



The numerator is exponentially lower than the denominator, so no long division.
The denominator seems not to factor out into anything... I tried doing a perfect squares situation, by factoring x out of the first two terms, but to no avail... Am I doing something wrong?
 
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  • #2
Try a u substitution u=x^3-4*x-6. Numerator look familiar?
 
Last edited:
  • #3
Wow, I'm an idiot... hahaha... Too busy trying my new integration skills and forgot substitution.
 
  • #4
Substitution is one of the first techniques you learn, and is one of the simplest to use. So that should be one that you think about using first. Even if it's not applicable, you haven't wasted that much time.
 

1. What is integration by partial fractions?

Integration by partial fractions is a method used in calculus to integrate rational functions, which are functions that can be expressed as the ratio of two polynomials. It involves breaking down a complex rational function into simpler partial fractions that can be integrated separately.

2. When is integration by partial fractions used?

This method is used when integrating rational functions that cannot be easily integrated by other methods, such as substitution or integration by parts. It is also used in applications such as differential equations and Laplace transforms.

3. How do you perform integration by partial fractions?

To perform integration by partial fractions, you first need to factor the denominator of the rational function into its irreducible factors. Then, for each unique factor, you set up a partial fraction with a variable as the numerator and a constant as the denominator. Finally, you solve for the constants by equating the coefficients of the original rational function with the coefficients of the partial fractions.

4. What are the benefits of using integration by partial fractions?

One of the main benefits of using integration by partial fractions is that it allows for the integration of complex rational functions that cannot be integrated using other methods. It also simplifies the integration process by breaking down a complex function into smaller, more manageable parts.

5. Are there any limitations to integration by partial fractions?

This method can only be used for integrating rational functions. It cannot be applied to other types of functions, such as trigonometric or exponential functions. Additionally, it can be time-consuming and may involve tedious algebraic manipulations in some cases.

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