Mister Exam

(2x-3)(5-x)+5=y canonical form

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The solution

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5 - y + (-3 + 2*x)*(5 - x) = 0
$$- y + \left(5 - x\right) \left(2 x - 3\right) + 5 = 0$$
-y + (5 - x)*(2*x - 3) + 5 = 0
Detail solution
Given line equation of 2-order:
$$- y + \left(5 - x\right) \left(2 x - 3\right) + 5 = 0$$
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
$$a_{11} = -2$$
$$a_{12} = 0$$
$$a_{13} = \frac{13}{2}$$
$$a_{22} = 0$$
$$a_{23} = - \frac{1}{2}$$
$$a_{33} = -10$$
To calculate the determinant
$$\Delta = \left|\begin{matrix}a_{11} & a_{12}\\a_{12} & a_{22}\end{matrix}\right|$$
or, substitute
$$\Delta = \left|\begin{matrix}-2 & 0\\0 & 0\end{matrix}\right|$$
$$\Delta = 0$$
Because
$$\Delta$$
is equal to 0, then
Given equation is straight line
- reduced to canonical form
The center of the canonical coordinate system in OXY
$$x_{0} = \tilde x \cos{\left(\phi \right)} - \tilde y \sin{\left(\phi \right)}$$
$$y_{0} = \tilde x \sin{\left(\phi \right)} + \tilde y \cos{\left(\phi \right)}$$
$$x_{0} = 0 \cdot 0$$
$$y_{0} = 0 \cdot 0$$
$$x_{0} = 0$$
$$y_{0} = 0$$
The center of canonical coordinate system at point O
(0, 0)

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:
$$- y + \left(5 - x\right) \left(2 x - 3\right) + 5 = 0$$
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
$$a_{11} = -2$$
$$a_{12} = 0$$
$$a_{13} = \frac{13}{2}$$
$$a_{22} = 0$$
$$a_{23} = - \frac{1}{2}$$
$$a_{33} = -10$$
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
$$I_{1} = -2$$
     |-2  0|
I2 = |     |
     |0   0|

$$I_{3} = \left|\begin{matrix}-2 & 0 & \frac{13}{2}\\0 & 0 & - \frac{1}{2}\\\frac{13}{2} & - \frac{1}{2} & -10\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}- \lambda - 2 & 0\\0 & - \lambda\end{matrix}\right|$$
     | -2   13/2|   | 0    -1/2|
K2 = |          | + |          |
     |13/2  -10 |   |-1/2  -10 |

$$I_{1} = -2$$
$$I_{2} = 0$$
$$I_{3} = \frac{1}{2}$$
$$I{\left(\lambda \right)} = \lambda^{2} + 2 \lambda$$
$$K_{2} = - \frac{45}{2}$$
Because
$$I_{2} = 0 \wedge I_{3} \neq 0$$
then by line type:
this equation is of type : parabola
$$I_{1} \tilde y^{2} + 2 \tilde x \sqrt{- \frac{I_{3}}{I_{1}}} = 0$$
or
$$\tilde x - 2 \tilde y^{2} = 0$$
$$\tilde y^{2} = - \frac{\tilde x}{2}$$
- reduced to canonical form