Re: arctan(x)/x^2



This is the third time I'm posting :) for some reason my post doesn't
appear.

Here is my comment:

Set

U = arctan(x) dV = 1/x^2 dx
dU = 1/(1+x^2)dx V = -1/x

result = -arctan(x)/x + Integral[1/(x(1+x^2))]

Now decompose, 1/(x(1+x^2)) = 1/x - x/(1+x^2) and integrating this
term by term is easy and one gets
lnx-(1/2)ln(1+x^2) + C =ln(x/Sqrt(1+x^2)) + C

Hence, result = -arctan(x)/x + ln(x/Sqrt(1+x^2)) + C where C is just a
constant.

I hope this helps,

Turkish Mathematician

.



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