Integrating 2/((e^(-x))+1): Solving the Unknown Integral

[bigdummy3000]

Homework Statement

integral of 2/((e^(-x))+1)

Homework Equations

how do you do this?

The Attempt at a Solution

no freaking clue! this is the BS i came up with

2(x-ln(e^-x + 1) + C)

 

[Dunkle]

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

 

[bigdummy3000]

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

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...

 

[Cyosis]

If $u=e^x+1$ then du=?