expected output from log of negative number

[Jordi Gutiérrez Hermoso]

On 13/06/2008, E. Joshua Rigler <relgire at gmail.com> wrote:
 > If I type log10(-1), I get a complex number back whose real part is the
 >  log of the absolute value of the argument, and whose imaginary part is
 >  always equal to 1.36438.  What's more, I get similar behavior with a
 >  natural log, but the imaginary part is always equal to Pi.


Uhm, do you know about branch cuts? That's just the principal branch
 of the logarithm, it is (-pi,pi], placing the cut on the negative
 imaginary axis.

 If you've never seen complex analysis, this might not make much sense.

 - Jordi G. H.