Can some one explain why I am getting this wrong

  • Thread starter viciousp
  • Start date
  • #1
51
0
Can some one explain why I am getting this wrong[SOLVED]

Homework Statement


Evaluate
[tex]\int ln(x+x^{2}) dx[/tex]

Homework Equations





The Attempt at a Solution


I integrated by parts to get down to [tex]xln(x+x^{2})-\int \frac{(2x-1)}{x+1}[/tex] I set [tex] u=1+x[/tex] which led to [tex]du=1 dx[/tex] and [tex]x=u-1[/tex] after so evaluation I got down to [tex]-(\int 2 du -\int \frac{1}{u} du)[/tex] and after more substitution and evaluation I got down to [tex]xln(x+x^{2})+ln\left|1+x \right|-2-2x +C[/tex], but my book says that I should have only got -2x and not that extra -2
 
Last edited:

Answers and Replies

  • #2
51
0
Nevermind I figured it out
 
  • #3
1,101
3
Huh weird, this same problem was solved yesterday. Which book are you using for calculus if you don't mind me asking?
 
  • #4
51
0
Thomas Calculus, I still don't get how I messed up on substitution but I just long divided and got the answer
 
  • #5
rock.freak667
Homework Helper
6,230
31
You didn't need to use integration by parts though.
 

Related Threads on Can some one explain why I am getting this wrong

Replies
3
Views
829
Replies
1
Views
791
Replies
7
Views
1K
Replies
2
Views
458
Replies
3
Views
1K
Replies
5
Views
4K
  • Last Post
Replies
2
Views
833
  • Last Post
Replies
3
Views
980
  • Last Post
Replies
5
Views
639
  • Last Post
Replies
1
Views
899
Top