# How to prove

1. Sep 10, 2008

### epkid08

How would someone go about proving:

$$\Im (ln(-|x|))=\pi$$ for all reals, x, when the answer takes the form, a + bi.

2. Sep 10, 2008

### Hurkyl

Staff Emeritus
What's wrong with direct calculation?

3. Sep 11, 2008

### mathman

Negative real numbers can be expressed in polar coordinates as re(pi)i. Take the log and you get ln(r)+(pi)i.