Greetings -(adsbygoogle = window.adsbygoogle || []).push({});

This integral is part of a larger problem I'm working on - I'm stuck (I Think)

Here's the integral:

[tex] = \int -\frac{e^{-x}}{e^{-3x}(1+e^x)}dx[/tex]

I've tried some algebra and substitutions:

[tex] = \int -\frac{e^{2x}}{(1+e^x)}dx[/tex]

[tex] = u=e^x[/tex]

[tex] = du=e^x dx[/tex]

[tex] = \int -\frac{u}{(1+u)}du[/tex]

Is this correct? Is this a standard form for something? - looking like ln()?

OR

could go:

[tex] = \int -\frac{e^{-x}}{e^{-3x}(1+e^x)}dx[/tex]

[tex] = \int -\frac{1}{e^{-2x} +e^{-x}}dx[/tex]

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Integration Question

**Physics Forums | Science Articles, Homework Help, Discussion**