ellipsoide avec axes

eq1: (3 * x^(2)) + (2 * (x * y)) + (x * z) + (3 * y^(2)) + (y * z) + (4 * z^(2)) = 18
A: (1, 1, 1)
B = Intersect(xAxis, zAxis)
f = Line(B, A)
C: (1, 1, -2)
D = Intersect(zAxis, f)
g = Line(D, C)
E: (1, -1, 0)
F = Intersect(g, zAxis)
h = Line(F, E)