# Complex function ?

1. Nov 1, 2011

### PeetPb

hi,
I'd like to ask whether the function f:y=|ln(x)| (|| denotes the absolute value) is complex. I'm a little bit confused because it is defined also for negative numbers in reals. Is the "negative part" classified as a complex function even if it has no imaginary part ?

thanx

2. Nov 1, 2011

### mathman

Real numbers may be positive or negative. Real numbers are a subset of complex numbers where the imaginary part is 0, whether the real part is positive or negative.

3. Nov 1, 2011

### PeetPb

Thanks, my question is , can I include that part of the plot where the independent variable is negative in real analysis ?

4. Nov 2, 2011

### mathman

If x is < 0, ln(x) is imaginary, but |ln(x)| is non-negative real. There is no rule that says you can't plot it.