Re: Cube root of -1 and 1
- To: mathgroup at smc.vnet.net
- Subject: [mg91032] Re: Cube root of -1 and 1
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Mon, 4 Aug 2008 03:23:08 -0400 (EDT)
- References: <g6h5fm$h26$1@smc.vnet.net>
Hi, because (-1)^(1/3) is not -1, it is 1/2 + (I/2)*Sqrt[3] Regards Jens Bob F wrote: > Could someone explain why Mathematica evaluates these so differently? > > In[53]:= > > (Sqrt[36] - 7)^(1/3) > (Sqrt[36] - 5)^(1/3) > > Out[53]= (-1)^(1/3) > > Out[54]= 1 > > In other words why isn't (-1)^1/3 expressed as -1 ?? > > Thanks... > > -Bob >