1. May 25, 2009 #1

   bigdummy3000

   

   1. The problem statement, all variables and given/known data
   
   
   
   integral of 2/((e^(-x))+1)
   
   2. Relevant equations
   
   how do you do this?
   
   
   
   3. The attempt at a solution
   
   no freaking clue! this is the BS i came up with
   
   2(x-ln(e^-x + 1) + C)

    

   bigdummy3000, May 25, 2009
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3. May 25, 2009 #2

   Dunkle

   

   You can rewrite the integrand and then use a simple substitution. Hint: multiply the numerator and denominator by e^x and then simplify.

    

   Last edited: May 25, 2009

   Dunkle, May 25, 2009
4. May 25, 2009 #3

   bigdummy3000

   

   so then...i want to find the integral of e^x/(e^x + 1)...and i think i want to use substitution? u = e^x + 1. but then i do something wrong somewhere...i'm getting retarded answers...

    

   bigdummy3000, May 25, 2009
5. May 25, 2009 #4

   Cyosis

   

   Homework Helper

   If [itex]u=e^x+1[/itex] then du=?

    

   Cyosis, May 25, 2009

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