View Full Version : Quick, need help with two indefinite integrals!
WakeZero
20-05-2002, 13:09
Can anyone integrate these? They have stumped me! Any help would be appreciated :D
1 / (1 + e^x)
and
(e^x) / (1 + e^2x)
Christie Miller
20-05-2002, 13:15
try
http://www.integrals.com
to get the answers you are looking for.
For the second integral, use u substitution:
/
|e^x
|-------------dx
|1+e^(2x)
/
/
|e^x dx
|--------------
|1+(e^x)^2
/
Now, let u = e^x
so du = e^x dx
Substituting, we have:
/
|1
|------------du
|1 + u^2
/
= arctan(u) + C
= arctan(e^x) + C
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