# Math Help - Value of this indefinite integral

1. ## Value of this indefinite integral

Can you help me please?
Which is the value of this integral?

$
\displaystyle\int_{0}^{\infty}\displaystyle\frac{l nx}{1+x^2}dx
$

Thanks

2. That's a definite integral.

What is lu(x)? Did you mean ln(x)?

3. it's finite and its value is zero.

put $x=\frac1t.$

4. Originally Posted by Bruno J.
That's a definite integral.

What is lu(x)? Did you mean ln(x)?
Yes you are right

Can you help me?

5. Originally Posted by Krizalid
it's finite and its value is zero.

put $x=\frac1t.$

Slick! Try it, osodud.