Re: ComplexExpand confusion

*To*: mathgroup at smc.vnet.net*Subject*: [mg60132] Re: ComplexExpand confusion*From*: "Scout" <not at nothing.net>*Date*: Sun, 4 Sep 2005 03:01:55 -0400 (EDT)*References*: <dfbejf$im2$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

<mike_in_england2000 at yahoo.co.uk> > Hi > > The Mathematica help system says that > > "ComplexExpand[expr] expands expr assuming that all variables are > real." > > which is fine and explains why expressions such as > ComplexExpand[Conjugate[x +I y]] work.All seems obvious so far. > > What is confusing me though is why does > > ComplexExpand[(-1)^(1/4)] > > give the result > > (1 + I)/Sqrt[2] > > I know this the correct result but in the expression (-1)^(1/4) there > are no variables. The numbers involved are real so what on earth is > ComplexExpand doing? Is this a stupid question? Should I have drank > more coffee before posting this. > > Thanks > Mike > (-1)^(1/4) is an EXPRESSION that has "no sense" in Reals but it's defined only in the Complex domain... ~Scout~