Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Compute integral
Replies: 7   Last Post: May 2, 2014 1:36 PM

 Search Thread: Advanced Search

 Messages: [ Previous | Next ]
 Jeremy Johnson Posts: 11 Registered: 2/27/14
Re: Compute integral
Posted: May 2, 2014 6:31 AM
 Plain Text Reply

On Friday, May 2, 2014 12:50:45 AM UTC-4, coote...@gmail.com wrote:
> Compute the integral from 0 to 1 of ln(1+x)/(1+x^2)dx. Hint: Use the substitution y+1=2/(x+1)
>
>
>
> I'm pretty sure I need to get this in the form of the integral of ln u du. So I use the substitution given and let u = 2/(x+1) but when I compute the derivative of this I get [(x+1)*0 - 2(1)]/(1+x)^2 = -2 /(1+x)^2 which does not equal 1/(1+x^2) like I need. I didnt get too far trying integration by parts but maybe that is the way to go? I doubt it because of the hint so pretty sure I am just missing something getting it in the form of ln u du.
>
>
>
> Any help is appreciated! Thanks! This is just a practice problem for a final and not something I have to turn in.

I haven't looked through all the comments closely yet but to clear things up I did mean the integral of
ln(1+x)
------
(1+x^2)

Also, this is a practice problem for a Real Analysis II class. I wish I as still in Calc II.
Thanks for the replies!

Date Subject Author
5/2/14 Jeremy Johnson
5/2/14 Math Lover
5/2/14 Roland Franzius
5/2/14 quasi
5/2/14 Jeremy Johnson
5/2/14 quasi
5/2/14 Peter Percival
5/2/14 Virgil

© The Math Forum at NCTM 1994-2018. All Rights Reserved.