unsimplifed result from expand
- Subject: unsimplifed result from expand
- From: Barton Willis
- Date: Thu, 31 Mar 2011 06:16:07 -0500
Another example:
(%i32) p : z^3-2^(3/2)*%i*z^2-4*z^2+2^(5/2)*%i*z+2*z;
(%o32) z^3-2^(3/2)*%i*z^2-4*z^2+2^(5/2)*%i*z+2*z
(%i33) divide(p, (z-2-sqrt(2)*%i),z);
(%o33) [z^2+((sqrt(2)-2^(3/2))*%i-2)*z,-(2^(3/2)-2^(5/2))*%i-2^(3/2)*%i]
We need to apply expand twice to simplify the remainder to zero:
(%i34) expand(%);
(%o34) [z^2-2^(3/2)*%i*z+sqrt(2)*%i*z-2*z,2^(5/2)*%i-2^(5/2)*%i]
(%i35) expand(%);
(%o35) [z^2-2^(3/2)*%i*z+sqrt(2)*%i*z-2*z,0]
Also:
(%i37) gcd(p, diff(p,z),z), gcd : spmod, algebraic : true;
(%o37) 1
(%i38) gcd(p, diff(p,z),z), gcd : subres, algebraic : true;
(%o38) z-sqrt(2)*%i-2
--Barton