How to Integrate ln(x+1)/x^2 using Partial Fractions

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In summary, the conversation involves finding the integral of ln(x+1)/x^2 and using integration by parts to solve it. The solution involves finding the coefficients A and B in the partial fraction and then finding the integration of ln(x+1)/x and 1/x+1. There was an error in the partial fraction where the ln function was not included in the right hand side, making it impossible to equate the coefficients.
  • #1
nameVoid
241
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[tex]
\int \frac{ln(x+1)}{x^2}dx
[/tex]
[tex]
u=x+1
[/tex]
[tex]
\int\frac{lnu}{(u-1)^2}du
[/tex]
[tex]
\int \frac{A}{u-1}+\frac{B}{(u-1)^2}du
[/tex]
[tex]
lnu=A(u-1)+B
[/tex]
[tex]
B=0,A=ln2
[/tex]
[tex]
\int \frac{ln2}{u-1}du
[/tex]
[tex]
ln2ln|x|+C
[/tex]
 
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  • #2
You have to do integration by parts.
Int[ln(x+1)/x^2] = ln(x+1)*intg(1/x^2) - Intg{[Intg(1/x^2)*d/dx[ln(x+1)]}
Now proceed.
 
  • #3
where is the error
 
  • #4
I = -1/x*ln(x+1) - int[(-1/x)*1/(x+1)]
= -1/x*ln(x+1) + int(1/x) - int1/(x+1)
Now find the integration.
In your partial factor, there is no ln function in the right hand side. So you can't equate the coefficients.
 

1. What is a miscellaneous integral?

A miscellaneous integral is an indefinite integral that does not fit into any specific category. It is often a combination of different types of integrals or involves functions that cannot be easily integrated.

2. How is a miscellaneous integral solved?

A miscellaneous integral is solved using various techniques such as substitution, integration by parts, partial fractions, and trigonometric identities. It may also require creative manipulation and algebraic rearrangement.

3. What are some common examples of miscellaneous integrals?

Some common examples of miscellaneous integrals include integrals involving inverse trigonometric functions, logarithmic functions, and higher-order polynomials. They may also involve special functions such as the exponential and gamma functions.

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5. How can I improve my skills in solving miscellaneous integrals?

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