Solving $\displaystyle \int \frac{\ln\left(x^2+2\right)}{(x+2)^2}dx$ by Parts

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Discussion Overview

The discussion revolves around the integral $\displaystyle \int \frac{\ln\left(x^2+2\right)}{(x+2)^2}dx$ and explores methods for solving it, particularly focusing on integration by parts and the potential use of partial fraction decomposition. The conversation includes considerations of alternative methods and the value of creative problem-solving in mathematics.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant presents an attempt at solving the integral using integration by parts, leading to a new integral $\displaystyle \int \frac{x}{\left(x^2+2\right)\cdot (x+2)}dx$.
  • Another participant questions the aversion to partial fraction decomposition, suggesting it as the best method to proceed with the problem.
  • A third participant agrees with the use of partial fractions and proposes a specific form for the decomposition.
  • One participant expresses support for exploring alternative methods, emphasizing the importance of creativity in mathematical problem-solving.

Areas of Agreement / Disagreement

There is a general agreement among some participants that partial fraction decomposition is a suitable method for solving the integral. However, there is also a recognition of the value in seeking alternative approaches, indicating a divergence in preferences for problem-solving strategies.

Contextual Notes

The discussion does not resolve the question of whether partial fractions or another method is definitively better, and the exploration of alternative methods remains open-ended.

juantheron
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$\displaystyle \int \frac{\ln\left(x^2+2\right)}{(x+2)^2}dx$

$\bf{My\; Try::}$ Given $\displaystyle \int \ln \left(x^2+2\right)\cdot \frac{1}{(x+2)^2}dx$

Using Integration by parts, we get

$\displaystyle = -\ln\left(x^2+2\right)\cdot \frac{1}{(x+2)} + 2\int \frac{x}{\left(x^2+2\right)\cdot (x+2)}dx$

Is there is any other method by which we can solve the Integral

$\displaystyle \int \frac{x}{\left(x^2+2\right)\cdot (x+2)}dx$ other then partial fraction.

Help me

Thanks
 
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Why the aversion to partial fraction decomposition? I think it is the best course of action for continuing. :D
 
I agree with Mark, the best strategy would be partial fractions.

Try $\displaystyle \begin{align*} \frac{A\,x + B}{x^2 + 2} + \frac{C}{x + 2} \equiv \frac{x}{ \left( x^2 + 2 \right) \left( x + 2 \right) } \end{align*}$ for your partial fraction decomposition.
 
Thanks Markfl and prove it.
 
While partial fractions is fine/the standard way, asking for an alternative way is something I feel should always be encouraged (and never discouraged) in mathematics. Looking for alternative ways to do problems builds one's creativity far better than sticking to the usual methods.
 

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