# Solution to an integral problem

1. Oct 19, 2011

### BLUE_CHIP

1. The problem statement, all variables and given/known data

The solution to the integral: $f(r) = \int{ \frac{1}{r} e^{-kr}dr}$

st. $k = const ; k\in ℝ$

2. Relevant equations

Does this integral have a solution.

3. The attempt at a solution

The obvious method here might be integration by parts this being a product of functions on r. The problem arises in that the exponent does not disappear under differentiation or integration and neither does the 1/r function.

Just affirmation that a solution exists would be sufficient.

Thanks

2. Oct 19, 2011

### phyzguy

3. Oct 19, 2011

### dextercioby

Well, the antiderivative you're looking for may not be expressible in terms of elementary functions, but the its definite integral between 0 and +infinity is a particularly nice number.

4. Oct 19, 2011

### BLUE_CHIP

Thank you very much.