I checked a few cases and this does not work in general. So I will change the maximum degree to 2 in pw 2.3.2.
Rich
----- Original Message -----
From: "Alexey Beshenov" <al at beshenov.ru>
To: <maxima at math.utexas.edu>
Sent: Saturday, December 20, 2008 8:13 AM
Subject: Re: [Maxima] pw.mac version 2.3.1
On Saturday 20 December 2008 15:54:15 Barton Willis wrote:
> What's the story? The equation x^3-23*x^2-71*x-11 = 0 has three
> real roots, but the roots expressed in terms of radicals involves
> %i. So Maxima wrongly assumes that these solutions are nonreal.
trigsimp & rectform do the trick.
(%i1) s : map('rhs, solve(x^3-23*x^2-71*x-11))$
(%i2) map ('imagpart, s);
(%o2) ...
(%i3) map (lambda([e], is(imagpart(e)=0)), s);
(%o3) [false,false,false]
(%i4) map (lambda([e], is(equal(imagpart(e),0))), s);
(%o4) [true,true,true]
(%i5) map (lambda([e], freeof(%i,e)), s);
(%o5) [false,false,false]
(%i6) map (lambda([e], freeof(%i, trigsimp(rectform(e)))), s);
(%o6) [true,true,true]
--
Prickle Prickle, Aftermath 62 YOLD 3174
Alexey Beshenov http://beshenov.ru/
_______________________________________________
Maxima mailing list
Maxima at math.utexas.edu
http://www.math.utexas.edu/mailman/listinfo/maxima