Given line equation of 2-order:
$$4 x^{2} - 8 x + 2 y^{2} - 4 y + 10 = 0$$
This equation looks like:
$$a_{11} x^{2} + 2 a_{12} x y + 2 a_{13} x + a_{22} y^{2} + 2 a_{23} y + a_{33} = 0$$
where
$$a_{11} = 4$$
$$a_{12} = 0$$
$$a_{13} = -4$$
$$a_{22} = 2$$
$$a_{23} = -2$$
$$a_{33} = 10$$
The invariants of the equation when converting coordinates are determinants:
$$I_{1} = a_{11} + a_{22}$$
|a11 a12|
I2 = | |
|a12 a22|
$$I_{3} = \left|\begin{matrix}a_{11} & a_{12} & a_{13}\\a_{12} & a_{22} & a_{23}\\a_{13} & a_{23} & a_{33}\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}a_{11} - \lambda & a_{12}\\a_{12} & a_{22} - \lambda\end{matrix}\right|$$
|a11 a13| |a22 a23|
K2 = | | + | |
|a13 a33| |a23 a33|
substitute coefficients
$$I_{1} = 6$$
|4 0|
I2 = | |
|0 2|
$$I_{3} = \left|\begin{matrix}4 & 0 & -4\\0 & 2 & -2\\-4 & -2 & 10\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}4 - \lambda & 0\\0 & 2 - \lambda\end{matrix}\right|$$
|4 -4| |2 -2|
K2 = | | + | |
|-4 10| |-2 10|
$$I_{1} = 6$$
$$I_{2} = 8$$
$$I_{3} = 32$$
$$I{\left(\lambda \right)} = \lambda^{2} - 6 \lambda + 8$$
$$K_{2} = 40$$
Because
$$I_{2} > 0 \wedge I_{1} I_{3} > 0$$
then by line type:
this equation is of type : imaginary ellipse
Make the characteristic equation for the line:
$$- I_{1} \lambda + I_{2} + \lambda^{2} = 0$$
or
$$\lambda^{2} - 6 \lambda + 8 = 0$$
Solve this equation$$\lambda_{1} = 4$$
$$\lambda_{2} = 2$$
then the canonical form of the equation will be
$$\tilde x^{2} \lambda_{1} + \tilde y^{2} \lambda_{2} + \frac{I_{3}}{I_{2}} = 0$$
or
$$4 \tilde x^{2} + 2 \tilde y^{2} + 4 = 0$$
$$\frac{\tilde x^{2}}{1^{2}} + \frac{\tilde y^{2}}{\left(\sqrt{2}\right)^{2}} = -1$$
- reduced to canonical form