ASKSAGE: Sage Q&A Forum - Latest question feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 14 Aug 2017 05:10:55 -0500Sage wrongly suggests there are only trivial solutions, why?https://ask.sagemath.org/question/38519/sage-wrongly-suggests-there-are-only-trivial-solutions-why/ I have a system of two quadratic equations which I want to solve. WolframAlpha shows me whole families of solution, but sage says there are only trivial solutions. The equations are
\begin{align}
d\cdot\lvert\alpha\rvert^2 + \alpha^* \beta + \alpha\beta^* ==&0,
\end{align}
\begin{align}
d\cdot\lvert\beta\rvert^2 + \alpha^* \beta + \alpha\beta^* ==&0,
\end{align}
where $d$ is constant and I want to solve for the complex numbers $\alpha, beta$
I have the following minimal working example
var('a,b,q')
assume(a, 'complex')
assume(b, 'complex')
assume(q, 'real')
eq(x,y) = q*norm(x) + conjugate(x)*y + x*conjugate(y)
solution = solve([eq(a,b) == 0, eq(b,a) == 0], [a,b])
polySolution = solve([eq(a,b) == 0, eq(b,a) == 0], [a,b], to_poly_solve=True)
and the output then is
sage: solution
[[a == 0, b == 0]]
sage: polySolution
[[a == 0, b == 0]]
which is simply not correct.
Now, as I said, I have found solutions with WolframAlpha, but the next candidate I have to compute gives 18 equations in 5 complex variables, which I cannot possibly solve with WA. Sage, again, tells me that there are only trivial solutions, but because of this smaller example presented here, I believe that that is wrong.
Does anyone know how to force sage to give solutions?Jo BeMon, 14 Aug 2017 05:10:55 -0500https://ask.sagemath.org/question/38519/