compute the integral

compute the integral

Postby Infernum » Tue Oct 09, 2007 3:40 am

[tex]\int_{}\frac{1}{\ln x}(1-\frac{1}{\ln x}) dx[/tex]
Infernum
 
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My solution

Postby ins-en » Tue Oct 09, 2007 3:01 pm

This integral is very simple but is nice. My solution is the following:
[tex]\int \frac{1}{lnx}\left(1-\frac{1}{lnx}\right)\,dx[/tex] may be represented in th following way:
[tex]\int \frac{1}{lnx}\,dx - \int \left(\frac{1}{lnx}\right)^{2}\,dx[/tex]
Integration by parts ot the first integral gives that it is equal to:
[tex]\frac{x}{lnx} + C + \int \left(\frac{1}{lnx}\right)^{2}\,dx - \int \left(\frac{1}{lnx}\right)^{2}\,dx[/tex]
So the final answer is: [tex]\frac{x}{lnx} + C[/tex]

ins-en
 
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