1 | initial version |
There is no inconsistency or bug, but a misunderstanding: the linear equation for v1
has a single solution only if the coefficient of v1
is nonzero. If the coefficient of v1
is zero, then the equation puts no restriction on v1
. (So the linear equation is not always enough to determine v1
.)
The coefficient of v1
in the linear equation is di + 3/5*a^3 + 3/5*a^2 + 4/5
. Indeed, it vanishes for some of the solutions (to check: do Id.variety(QQbar)
, substitute each solution into the coefficient, and call the radical_expression()
method).