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2x^2+2y^2-8sqrt(2)y canonical form

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The solution

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   2      2         ___    
2*x  + 2*y  - 8*y*\/ 2  = 0
$$2 x^{2} + 2 y^{2} - 8 \sqrt{2} y = 0$$
2*x^2 + 2*y^2 - 8*sqrt(2)*y = 0
Detail solution
Given line equation of 2-order:
$$2 x^{2} + 2 y^{2} - 8 \sqrt{2} y = 0$$
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
$$a_{11} = 2$$
$$a_{12} = 0$$
$$a_{13} = 0$$
$$a_{22} = 2$$
$$a_{23} = - 4 \sqrt{2}$$
$$a_{33} = 0$$
To calculate the determinant
$$\Delta = \left|\begin{matrix}a_{11} & a_{12}\\a_{12} & a_{22}\end{matrix}\right|$$
or, substitute
$$\Delta = \left|\begin{matrix}2 & 0\\0 & 2\end{matrix}\right|$$
$$\Delta = 4$$
Because
$$\Delta$$
is not equal to 0, then
find the center of the canonical coordinate system. To do it, solve the system of equations
$$a_{11} x_{0} + a_{12} y_{0} + a_{13} = 0$$
$$a_{12} x_{0} + a_{22} y_{0} + a_{23} = 0$$
substitute coefficients
$$2 x_{0} = 0$$
$$2 y_{0} - 4 \sqrt{2} = 0$$
then
$$x_{0} = 0$$
$$y_{0} = 2 \sqrt{2}$$
Thus, we have the equation in the coordinate system O'x'y'
$$a'_{33} + a_{11} x'^{2} + 2 a_{12} x' y' + a_{22} y'^{2} = 0$$
where
$$a'_{33} = a_{13} x_{0} + a_{23} y_{0} + a_{33}$$
or
$$a'_{33} = - 4 \sqrt{2} y_{0}$$
$$a'_{33} = -16$$
then equation turns into
$$2 x'^{2} + 2 y'^{2} - 16 = 0$$
Given equation is circle
        2            2     
\tilde x     \tilde y      
---------- + ---------- = 1
         2            2    
//  ___\\    //  ___\\     
||\/ 2 ||    ||\/ 2 ||     
||-----||    ||-----||     
|\  2  /|    |\  2  /|     
|-------|    |-------|     
\  1/4  /    \  1/4  /     

- reduced to canonical form
The center of canonical coordinate system at point O
        ___ 
(0, 2*\/ 2 )

Basis of the canonical coordinate system
$$\vec e_1 = \left( 1, \ 0\right)$$
$$\vec e_2 = \left( 0, \ 1\right)$$
Invariants method
Given line equation of 2-order:
$$2 x^{2} + 2 y^{2} - 8 \sqrt{2} y = 0$$
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
$$a_{11} = 2$$
$$a_{12} = 0$$
$$a_{13} = 0$$
$$a_{22} = 2$$
$$a_{23} = - 4 \sqrt{2}$$
$$a_{33} = 0$$
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
$$I_{1} = 4$$
     |2  0|
I2 = |    |
     |0  2|

$$I_{3} = \left|\begin{matrix}2 & 0 & 0\\0 & 2 & - 4 \sqrt{2}\\0 & - 4 \sqrt{2} & 0\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}2 - \lambda & 0\\0 & 2 - \lambda\end{matrix}\right|$$
              |               ___|
     |2  0|   |   2      -4*\/ 2 |
K2 = |    | + |                  |
     |0  0|   |     ___          |
              |-4*\/ 2      0    |

$$I_{1} = 4$$
$$I_{2} = 4$$
$$I_{3} = -64$$
$$I{\left(\lambda \right)} = \lambda^{2} - 4 \lambda + 4$$
$$K_{2} = -32$$
Because
$$I_{2} > 0 \wedge I_{1} I_{3} < 0$$
then by line type:
this equation is of type : circle
Make the characteristic equation for the line:
$$- I_{1} \lambda + I_{2} + \lambda^{2} = 0$$
or
$$\lambda^{2} - 4 \lambda + 4 = 0$$
$$\lambda_{1} = 2$$
$$\lambda_{2} = 2$$
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
$$2 \tilde x^{2} + 2 \tilde y^{2} - 16 = 0$$
        2            2     
\tilde x     \tilde y      
---------- + ---------- = 1
         2            2    
//  ___\\    //  ___\\     
||\/ 2 ||    ||\/ 2 ||     
||-----||    ||-----||     
|\  2  /|    |\  2  /|     
|-------|    |-------|     
\  1/4  /    \  1/4  /     

- reduced to canonical form