# How could I evaluate this IMPROPER integra?

1. Nov 3, 2007

### frasifrasi

Int from 1 to infinity of ln(X)/x^(3)

--> Any ideas on how to get started(mainly the technique)? thank you.

2. Nov 3, 2007

### Dick

You would first find an indefinite integral using integration by parts.

3. Nov 4, 2007

### benjyk

Let u = ln x and dv/dx = x^-3 and use integration by parts.
And see what happens as the upper bound of the integral tends to infinity.