# Indefinite integral

## Homework Statement

(e^-x)/(1+e^-x)dx

## Homework Equations

Integral of e^x function

## The Attempt at a Solution

I am completely lost with the problem, the fact that it is e^-x and not e^x has me stupped as well as the division.

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Try $u$-substitution.

so if I let u=1+e^-x?

yes?

so if I let u=1+e^-x?
Well, does it work?

I still cant figure it out so I gave up and will try again later

I still cant figure it out so I gave up and will try again later
When you do get back to it, answer this: What is $du$ when $u=1+e^{-x}$?

Will du = -e^-x dx