# Homework Help: Can't integrate the e s here

1. Sep 4, 2010

### Iskander

Can't integrate the "e"s here

1. The problem statement, all variables and given/known data
$$\int 2/e3x(6+e-3x)dx$$

2. Relevant equations
I have no idea as to what equations to use, other than $$\int$$ e$$u$$ du = e $$u$$ + C

3. The attempt at a solution
$$\int$$ 2/(6e3x +1) dx
u = 6e3x +1
du = 18e3x dx

and that's as far as I can get, I can't think of what else to do. HELP!!

2. Sep 4, 2010

### Mu naught

Re: Can't integrate the "e"s here

3. Sep 4, 2010

### eumyang

Re: Can't integrate the "e"s here

Is it supposed to be this?
$$\int \frac{2}{e^{3x}} (6 + e^{-3x}) dx$$

Or this?
$$\int \frac{2}{e^{3x} (6 + e^{-3x})} dx$$

If it's the second, then I wouldn't distribute the e^(3x) at all. I would move it to the numerator, and then use substitution: u = (6 + e^(-3x)). Try it and see what happens.

Last edited by a moderator: Sep 15, 2010