#2617: solve() can return undefined points as "solutions"
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Reporter: cwitty | Owner: was
Type: defect | Status: new
Priority: critical | Milestone: sage-4.3.1
Component: calculus | Keywords:
Work_issues: | Author:
Upstream: N/A | Reviewer:
Merged: |
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Comment(by kcrisman):
As it turns out, to_poly_solve can handle this sort of thing (see in
Maxima the share/contrib/rtest_to_poly_solver.mac line 1092). But we
would have to figure out a way to interpret the if statements properly
(for instance, to note that twice an integer plus one is not zero).
{{{
/* Sage Ticket 2617; see also Sage mailing list 18 March 2008 */
nicedummies(to_poly_solve(sin(x^2)/x,x));
%union(%if(2*%z0+1 # 0,[x = -sqrt(2*%pi*%z0+%pi)],%union()),
%if(2*%z0+1 # 0,[x = sqrt(2*%pi*%z0+%pi)],%union()),
%if(%z1 # 0,[x = -sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()),
%if(%z1 # 0,[x = sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()))$
nicedummies(to_poly_solve(sin(x^2)/x^2,x));
%union(%if(2*%z0+1 # 0,[x = -sqrt(2*%pi*%z0+%pi)],%union()),
%if(2*%z0+1 # 0,[x = sqrt(2*%pi*%z0+%pi)],%union()),
%if(%z1 # 0,[x = -sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()),
%if(%z1 # 0,[x = sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()))$
nicedummies(to_poly_solve(sin(x^2)/x^3,x));
%union(%if(2*%z0+1 # 0,[x = -sqrt(2*%pi*%z0+%pi)],%union()),
%if(2*%z0+1 # 0,[x = sqrt(2*%pi*%z0+%pi)],%union()),
%if(%z1 # 0,[x = -sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()),
%if(%z1 # 0,[x = sqrt(2)*sqrt(%pi)*sqrt(%z1)],%union()))$
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/2617#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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