id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
11941 Solve and assumptions too aggressive with cube root of negative numbers kcrisman burcin "#6515 did a great job helping us start to catch some assumptions when we do solving.
However, [http://ask.sagemath.org/question/824/real-solution-of-x38-0 this ask.sagemath.org post] catches a case where it's too aggressive, because Sage says that `(-1)^(1/3)` is not real.
{{{
sage: solve(x^3+1==0,x)
[x == 1/2*I*(-1)^(1/3)*sqrt(3) - 1/2*(-1)^(1/3), x == -1/2*I*(-1)^(1/3)*sqrt(3) - 1/2*(-1)^(1/3), x == (-1)^(1/3)]
sage: assume(x,'real')
sage: solve(x^3+1==0,x)
[]
}}}
What's weird about this is that the Maxima in Sage should just return `x==-1`.
{{{
(%i2) display2d:false;
(%o2) false
(%i3) solve(x^3+1=0,x);
(%o3) [x = -(sqrt(3)*%i-1)/2,x = (sqrt(3)*%i+1)/2,x = -1]
}}}
Not sure what's going on with that." defect needs_work major sage-7.6 symbolics pelegm Not yet reported upstream; Will do shortly. report upstream