Re: Re (-1)^(3/4) -> (-1+I)/Sqrt[2] ?

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg594] Re: [mg584] Re[mg557] (-1)^(3/4) -> (-1+I)/Sqrt[2] ?*From*: karl at faepds01.tu-graz.ac.at (Karl Unterkofler)*Date*: Thu, 23 Mar 1995 09:17:18 +0100

>> Does anybody know a core or standard package command that makes >> transformations like (-1)^(3/4) -> (-1+I)/Sqrt[2] ? > >There was a simple answer to my question, supplied by Robby Villegas of >WRI. > >Here it is: ComplexExpand. > >I missed it because there is nothing like ComplexExpand[(-1)^(3/4)] among >the examples given in The Book. This is a really common need, and I hope >it will appear as an example in future editions. I tried In[422]:= ComplexExpand[(-1)^(1/5)] // InputForm Out[422]//InputForm=Cos[Pi/5] + I*Sin[Pi/5] But want I want is Cos[ Pi/5] = (1+ Sqrt[5])/4 Any suggestions? karl unterkofler