The answer is -ln(1+e^-x). I'm not real sure how it got there.

Printable View

- Sep 3rd 2009, 02:43 PMjebckrintegrate (e^-x)/(1+e^-x)
The answer is -ln(1+e^-x). I'm not real sure how it got there.

- Sep 3rd 2009, 02:45 PMMatt Westwood
Are you familiar with ?

- Sep 3rd 2009, 02:48 PMTKHunny
Have you considered:

u = {whatever is in the denominator}

?? - Sep 3rd 2009, 02:54 PMjebckr
We havn't been taught that rule Matt.

And "u" substitution doesn't give me an ln. I doubt I'll be tested on this, but still wanted to know. Thanks Matt, the rule is something I need to know I guess. - Sep 3rd 2009, 02:59 PMMatt Westwood
Okay then, substitute . Get in terms of and and see what happens.

- Sep 3rd 2009, 03:00 PMMatt Westwood
- Sep 3rd 2009, 03:10 PMjebckr
ok, thanks. Got it.