Integration by substitution for (1+x)/(1-x)

Then du= dx and the integral of 1/u is ln(u)= ln(x-1).In summary, to integrate (1+x)/(1-x), you must first simplify the fraction by dividing 1+x by 1-x. This gives -1- 2/(x-1). You can then integrate -1 and -2/(x-1) separately. To integrate -2/(x-1), let u=x-1 and use the substitution method. The integral of 1/u is ln(u), which becomes ln(x-1) after substituting back in for u.
  • #1
cabellos6
31
0

Homework Statement


I want to integrate (1+x)/(1-x)


Homework Equations





The Attempt at a Solution


I have looked at many examples of substitution method - this one appears simple but I am not finishing the last step...

- I know you must first take u=(1-x)
- Then du = -dx

what happens with the numerator (1+x) as this would be the integral of -(1+x)du/u

id be very grateful if you could run me through the steps for this please.

thanks
 
Physics news on Phys.org
  • #2
You need to simplify the fraction first: dividing 1+ x by 1- x gives -1+ 2/(1-x)= -1- 2/(x-1). It's easy to integrate "-1" and to integrate -2/(x-1), let u= x-1.
 

1. What is integration by substitution?

Integration by substitution is a method used in calculus to find the integral of a function by substituting a variable with a new one. This technique is also known as the "chain rule" or "u-substitution."

2. How do you use integration by substitution for (1+x)/(1-x)?

To use integration by substitution for (1+x)/(1-x), we first substitute the variable (1-x) with a new variable u. Then, we find the derivative of u (du) and substitute it into the equation. This will give us an integral with only one variable, which we can then solve using basic integration techniques.

3. Why is integration by substitution useful for (1+x)/(1-x)?

Integration by substitution is useful for (1+x)/(1-x) because it simplifies the integral and makes it easier to solve. By substituting a new variable, we can reduce the complexity of the integral and solve it using basic integration rules.

4. What are the steps for integrating (1+x)/(1-x) using substitution?

The steps for integrating (1+x)/(1-x) using substitution are as follows:
1. Substitute the variable (1-x) with a new variable u.
2. Find the derivative of u (du) and substitute it into the equation.
3. Simplify the integral by substituting (1-x) with u.
4. Integrate the new equation using basic integration rules.
5. Substitute back the original variable (1-x) with u to get the final solution.

5. Can integration by substitution be used for any function?

Yes, integration by substitution can be used for any function. However, it is most effective for functions that are difficult to integrate using basic rules. It is a useful technique to simplify the integral and make it easier to solve.

Similar threads

  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
481
  • Calculus and Beyond Homework Help
Replies
8
Views
753
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
22
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
748
  • Calculus and Beyond Homework Help
Replies
27
Views
2K
  • Calculus and Beyond Homework Help
Replies
7
Views
690
Back
Top