I tried to integrate the following and got ...ummm...0=0

Can someone plase integrate it step by step ?

(cosw/(1+w^2)) from 0 to infinity

2. Hello,
Originally Posted by Altair
I tried to integrate the following and got ...ummm...0=0

Can someone plase integrate it step by step ?

(cosw/(1+w^2)) from 0 to infinity
Uh...

If you substitute $w=\tan \theta$, then $dw=(1+w^2) d \theta$

And the integral is then :
$I=\int_0^{\pi/2} \cos(\tan \theta) ~d\theta$

It looks more friendly but I don't know how to solve it

Otherwise, have you ever seen the residues theorem, in complex analysis ? The very first integral may be solved with the use of this theorem..