Re: How Mathematica select one of the roots?
- To: mathgroup@smc.vnet.net
- Subject: [mg12316] Re: [mg12237] How Mathematica select one of the roots?
- From: David Withoff <withoff@wolfram.com>
- Date: Thu, 7 May 1998 18:51:59 -0400
> Dear All! > > I have some question about Mathematica 3.0. > > When Mathematica 3.0 calculate > (-1.)^(1/3) > it generate complex value result > 0.5 + 0.8660254037844385*I. > > But when I try to Solve equation > x^3+1==0 > it generates three different roots. > > So, here is the question: > > "How Mathematica 3.0 select one of the roots in the first example?" > > Thanks in advance for any "real" answer! > > SY > S. Molyavko (-1.)^(1/3) selects the principal root. That is, p^q is defined by exp(q log(p)) using the principal value of the logarithm. Dave Withoff Wolfram Research