Evaluate the integral :

http://s291.photobucket.com/albums/l...howchi/int.jpg

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- May 2nd 2009, 02:05 AMsimplependulumEvaluate the integral
Evaluate the integral :

http://s291.photobucket.com/albums/l...howchi/int.jpg - May 2nd 2009, 06:12 AMrunning-gag
Hi

__Spoiler__: - May 2nd 2009, 06:21 AMNonCommAlg
let $\displaystyle \alpha > 0$ and put $\displaystyle x = \frac{1}{t}.$ then we get $\displaystyle \int \frac {dx}{x(1 + x^{\alpha})} = - \int \frac {t^{\alpha - 1}}{1+t^{\alpha}} \ dt = - \frac{1}{\alpha} \ln |1 + t^{\alpha}| + c=-\frac{1}{\alpha} \ln |1 + x^{-\alpha}| + c.$

- May 2nd 2009, 07:39 PMsimplependulum
Yes . It isn't difficult actually

but I was shocked and scared when my friend gave me this integral because the degree is too large 2009 (Crying) I had no confidence to solve at that time