# Transformation of a Cauchy-Euler equation

1. Mar 26, 2013

### jawhnay

1. The problem statement, all variables and given/known data
x2y'' - xy' = ln x

2. Relevant equations
The problem I'm having is what do I do with x = et or t = ln x.

3. The attempt at a solution
I know you have to start with x = et or t = ln x however I'm not sure what to do next...

2. Mar 26, 2013

### voko

You need to express $y' = \frac {dy} {dx}, \ y'' = \frac {d^2y} {dx^2}$ in terms of $\frac {dy} {dt}$ and $\frac {d^2y} {dt^2}$.