A stubborn integral

  • Thread starter boa_co
  • Start date
  • #1
11
0

Homework Statement


I have to integrate

[PLAIN]http://img69.imageshack.us/img69/4259/integral1.gif [Broken]

The Attempt at a Solution



This is how I did it

[PLAIN]http://img338.imageshack.us/img338/5508/integral12.gif [Broken]

wolfram says it is supposed to turnout like this

[PLAIN]http://img690.imageshack.us/img690/1462/integral13.gif [Broken]

Where does the extra 2 in the log come from?

Thanks
 
Last edited by a moderator:

Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
4,306
48
The answers are actually the same, up to a constant -2 ln(2).

With logarithms this is always tricky, because they satisfy
[tex]\ln(a \cdot b) = \ln(a) + \ln(b)[/tex]

Apparently Wolfram Alpha / Mathematica uses some other method to calculate the integral in which the 2 inside the log appear naturally.
 

Related Threads on A stubborn integral

Replies
11
Views
2K
Replies
5
Views
757
Replies
1
Views
1K
Replies
3
Views
1K
Replies
4
Views
2K
  • Last Post
Replies
0
Views
651
  • Last Post
Replies
16
Views
3K
  • Last Post
Replies
4
Views
910
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
7
Views
2K
Top