(-1)^(1/4)?



> From: Raymond Toy <toy at rtp>
> Date: 25 Sep 2001 13:48:22 -0400
> 
> 
> Currently, maxima says
> 
> (C21) solve(x^4+1=0,x);
> 
> 		1/4		   1/4		   1/4		    1/4
> (D21) [x = (- 1)    %I, x = - (- 1)   , x = - (- 1)    %I, x = (- 1)   ]
> 
> which is right, but I expected the answer to be powers of
> (1+%i)/sqrt(2).  I could add the rule
> 
> tellsimp((-1)^(1/4), (1+%i)/sqrt(2))
> 
> to get what I want.
> 
> A bug?


No.

(C6) solve(x^4+1=0,x);

                1/4                1/4             1/4              1/4
(D6)  [x = (- 1)    %I, x = - (- 1)   , x = - (- 1)    %I, x = (- 1)   ]
(C7) rectform(%);

          SQRT(2) %I   SQRT(2)        SQRT(2) %I   SQRT(2)
(D7) [x = ---------- - -------, x = - ---------- - -------, 
              2           2               2           2

                                SQRT(2)   SQRT(2) %I      SQRT(2) %I   SQRT(2)
                            x = ------- - ----------, x = ---------- + -------]
                                   2          2               2           2
(C8) polarform(%);

Is  x  positive, negative, or zero?

p;
              3 %I %PI          3 %I %PI          %I %PI        %I %PI
              --------        - --------        - ------        ------
                 4                 4                4             4
(D8)   [x = %E        , x = %E          , x = %E        , x = %E      ]
(C9) 


Note that the question in d7 is spurious and was asked only because I
was lazy and did not  preventthe  evaluaton of polarform(x)

-- 
Good luck

-Boris