# Homework Help: Find the continuous branch cut of a complex logarythm

1. Jun 7, 2012

### hachiroku

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

Find the continuous branch cut of a complex logarythm for C\[iy:y=>0]

One of the complex numbers, for example, is -4i

2. Relevant equations

I don´t understand what to do with the subset. How could I find the continuous branch cut in the subset?

3. The attempt at a solution

I found the main value: log(2)+i(3pi/2+2kpi)

Thanks

2. Jun 8, 2012

### jackmell

$$\log(z)=\ln|z|+i\arg(z)$$

What's that look like? I mean a picture of the real and imaginary parts of that function. You do Mathematica?