How can I integrate dx / (x^2 - 1)^2 without a substitution?

  • Thread starter aija
  • Start date
  • Tags
    Integrate
In summary, the conversation discusses the difficulty of integrating dx / (x^2 - 1)^2 and suggests trying a substitution such as x = cosh(t).
  • #1
aija
15
0

Homework Statement


integrate dx / (x^2 - 1)^2


Homework Equations





The Attempt at a Solution


There is nothing i can substitute to get rid of x. Except x=sqr(t), but then dx is 1/2sqr(t) so i get:

∫( dt / (t-1)^2 * 2sqr(t) )

and it's still impossible to integrate.
 
Physics news on Phys.org
  • #2
Try partial fractions decomposition, remembering that (x^2-1)=(x+1)(x-1)
 
  • #3
aija said:

Homework Statement


integrate dx / (x^2 - 1)^2


Homework Equations





The Attempt at a Solution


There is nothing i can substitute to get rid of x. Except x=sqr(t), but then dx is 1/2sqr(t) so i get:

∫( dt / (t-1)^2 * 2sqr(t) )

and it's still impossible to integrate.

A more-or-less standard substitution to try out when you see 'x^2-1' is x = cosh(t).
 

Related to How can I integrate dx / (x^2 - 1)^2 without a substitution?

1. What is the formula for integrating 1 / (x^2 - 1)^2?

The formula for integrating 1 / (x^2 - 1)^2 is ∫ 1 / (x^2 - 1)^2 dx = -1 / (4x(x^2 - 1)) + C.

2. How do you solve the integral of 1 / (x^2 - 1)^2?

To solve the integral of 1 / (x^2 - 1)^2, you can use the substitution method by letting u = x^2 - 1. Then, the integral becomes ∫ 1 / u^2 du, which can be solved using the power rule.

3. Can you explain the concept of partial fractions when integrating 1 / (x^2 - 1)^2?

Partial fractions is a technique used to simplify integrals of rational functions. For 1 / (x^2 - 1)^2, we can use partial fractions to rewrite the expression as A / (x - 1) + B / (x + 1) + C / (x - 1)^2 + D / (x + 1)^2, where A, B, C, and D are constants. This allows us to integrate each term separately.

4. Is there a special case when integrating 1 / (x^2 - 1)^2?

Yes, there is a special case when integrating 1 / (x^2 - 1)^2. If the denominator can be factored into (x - a)^2, then the integral can be solved using the substitution method with u = x - a. This will result in a simpler integral to solve.

5. Are there any real-life applications of integrating 1 / (x^2 - 1)^2?

Yes, integrating 1 / (x^2 - 1)^2 has various real-life applications in fields such as physics, engineering, and economics. For example, it can be used to calculate the electric field of an electric dipole or to determine the value of a resistor in an electrical circuit. It can also be used in economic models to analyze supply and demand functions.

Similar threads

  • Calculus and Beyond Homework Help
Replies
9
Views
746
  • Calculus and Beyond Homework Help
Replies
23
Views
983
  • Calculus and Beyond Homework Help
Replies
7
Views
737
  • Calculus and Beyond Homework Help
Replies
15
Views
802
  • Calculus and Beyond Homework Help
Replies
22
Views
1K
  • Calculus and Beyond Homework Help
Replies
8
Views
783
  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
365
  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
216
Back
Top