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CAS Matrix*Vector+Vector addition + const addition and Coefficients fail
In Progress
see https://www.geogebra.org/m/tmakcd2s
Line 45 ( only variable y evaluated  missing coeffs z)
q_x:=(y^(2))  z^(2)  ((2 * y) * z) + (2 * y)  1
cB:=Coefficients(q_x) ==>cB:={(1), ((2) * z) + 2, (z^(2))  1}
AlgebraView ===> {0, (1), (1), (1), 0, 0, (2), 0, 2, 0} correct
Line 26 (a_0=1 got 5  have to convert a to list, should be posible to compute Matrix*Vector+Vector?
X M X + a X + a_0 ===> x^(2) + (3 * y^(2))  z^(2)  ((4 * x) * y)  ((2 * y) * z) + (2 * x)  (2 * y)  5
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Sorry, Coefficients(quadric) only works in the Algebra View (as you've noticed).
For the other problems please say clearly
* which row is wrong
* what you get
* what you'd like to get
I see,
to Coefficents I have added a additional x^2 to force a correct result.

see Line 24 and Line 27
If I add a_0 : X M X + a X + a_0 ===> I got a 5 and not the value of a_0=1
even
X M X + a X + 1
>x² + 3y²  z²  4x y  2y z + 2x  2y + 5
Addition of Matrix*Vektor+Const goes wrong
I am missing a clear statement to convert list <==> vector, vector <==> list
list((1,2,3))={1,2,3}
vector({1,2,3})=(1,2,3)^T
Point({1,2,3})=(1,2,3)
it's pretty horrible to handle homogeneous coordinates in CAS
and Vector <==> Point
v:=Vector( Q)
is possible, but
V:=Point(v)
not....
V:=Point(v) <> V=(0,0,0)+v
v <> {x(v),y(v),z(v)}
Of course you can construct a workaround for almost everything, but in the sense of a clear and readable code it would be desirable to have explicit instructions?
BTW: the functions x(),y(),z() have a low halflife in CAS  and yes, I have workaround for ...
big ilogical bug
he hecho algunas cuentas y en el caso
X M X 3+6+1+2 lo que se calcula realmente es (X M X+9) 12 donde 9=3+6 y 12=3+6+1+2
he probado con otros numeros diferentes y la cuenta se hace de la misma manera
al menos sigue una logica erronea
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