Integration of Rational Functions by Partial Fractions

In summary, integrating rational functions by partial fractions involves breaking down a complex rational function into simpler fractions to make integration easier. This is done by factoring the denominator into linear factors and using undetermined coefficients to solve for the partial fractions. There are two main types of partial fractions: proper and improper, with improper fractions further divided into distinct and repeated linear factors. Not all rational functions can be integrated using this method, and there are special cases to consider such as repeated linear factors, complex roots, and common factors between the numerator and denominator.
  • #1
afcwestwarrior
457
0

Homework Statement



∫1/ x^3-1 dx, ok how would i do this

Homework Equations


∫dx/ x^2+a^2= 1/a tan^-1 (x/a) +c


i tried to simplify x^3-1 = (x+1)(x-1)(x+1)
 
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  • #2
afcwestwarrior said:
i tried to simplify x^3-1 = (x+1)(x-1)(x+1)

You've tried to factor out (x-1) from x3-1 which is a good start, however you might want to check your calculation again. Once you've re-done the factorization, we'll take it from there.
 
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  • #3
afcwestwarrior said:
i tried to simplify x^3-1 = (x+1)(x-1)(x+1)

Check this back...(x-1) is a factor, but divide it out again, your approach is correct though.
 

1. What is the purpose of integrating rational functions by partial fractions?

The purpose of integrating rational functions by partial fractions is to break down a complex rational function into simpler fractions that can be easily integrated using basic integration rules. This method is especially useful for integrating rational functions with denominators consisting of a product of linear factors.

2. How do you determine the partial fractions of a rational function?

To determine the partial fractions of a rational function, you first factor the denominator into linear factors. Then, for each distinct linear factor, you set up a fraction with that factor as the denominator and an undetermined coefficient as the numerator. You then use algebraic methods to solve for the unknown coefficients.

3. What are the different types of partial fractions?

There are two main types of partial fractions: proper and improper. Proper partial fractions have a smaller degree in the numerator than in the denominator, while improper partial fractions have equal or larger degrees in the numerator compared to the denominator. Improper partial fractions can be further divided into two types: distinct linear factors and repeated linear factors.

4. Can all rational functions be integrated using partial fractions?

No, not all rational functions can be integrated using partial fractions. This method only works for rational functions with denominators consisting of a product of linear factors. If the denominator contains any quadratic or higher order factors, a different integration method must be used.

5. Are there any special cases when integrating rational functions by partial fractions?

Yes, there are a few special cases to be aware of when integrating rational functions by partial fractions. First, if the denominator contains repeated linear factors, the corresponding partial fractions will have a numerator consisting of a constant and a polynomial in the variable. Second, if the denominator has complex roots, the partial fractions will involve complex numbers. Third, if the numerator and denominator share any common factors, they must be simplified before applying the partial fractions method.

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