Mister Exam

Other calculators

4x^2+y^2+z^2+4xy+4xz+2yz+2x+y+z-2=0 canonical form

The teacher will be very surprised to see your correct solution 😉

v

The graph:

x: [, ]
y: [, ]
z: [, ]

Quality:

 (Number of points on the axis)

Plot type:

The solution

You have entered [src]
              2    2            2                            
-2 + y + z + y  + z  + 2*x + 4*x  + 2*y*z + 4*x*y + 4*x*z = 0
$$4 x^{2} + 4 x y + 4 x z + y^{2} + 2 y z + z^{2} + 2 x + y + z - 2 = 0$$
4*x^2 + 4*x*y + 4*x*z + 2*x + y^2 + 2*y*z + y + z^2 + z - 2 = 0
Invariants method
Given equation of the surface of 2-order:
$$4 x^{2} + 4 x y + 4 x z + y^{2} + 2 y z + z^{2} + 2 x + y + z - 2 = 0$$
This equation looks like:
$$a_{11} x^{2} + 2 a_{12} x y + 2 a_{13} x z + a_{22} y^{2} + 2 a_{23} y z + a_{33} z^{2} + 2 a_{14} x + 2 a_{24} y + 2 a_{34} z + a_{44} = 0$$
where
$$a_{11} = 4$$
$$a_{12} = 2$$
$$a_{13} = 2$$
$$a_{14} = 1$$
$$a_{22} = 1$$
$$a_{23} = 1$$
$$a_{24} = \frac{1}{2}$$
$$a_{33} = 1$$
$$a_{34} = \frac{1}{2}$$
$$a_{44} = -2$$
The invariants of the equation when converting coordinates are determinants:
$$I_{1} = a_{11} + a_{22} + a_{33}$$
     |a11  a12|   |a22  a23|   |a11  a13|
I2 = |        | + |        | + |        |
     |a12  a22|   |a23  a33|   |a13  a33|

$$I_{3} = \left|\begin{matrix}a_{11} & a_{12} & a_{13}\\a_{12} & a_{22} & a_{23}\\a_{13} & a_{23} & a_{33}\end{matrix}\right|$$
$$I_{4} = \left|\begin{matrix}a_{11} & a_{12} & a_{13} & a_{14}\\a_{12} & a_{22} & a_{23} & a_{24}\\a_{13} & a_{23} & a_{33} & a_{34}\\a_{14} & a_{24} & a_{34} & a_{44}\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}a_{11} - \lambda & a_{12} & a_{13}\\a_{12} & a_{22} - \lambda & a_{23}\\a_{13} & a_{23} & a_{33} - \lambda\end{matrix}\right|$$
     |a11  a14|   |a22  a24|   |a33  a34|
K2 = |        | + |        | + |        |
     |a14  a44|   |a24  a44|   |a34  a44|

     |a11  a12  a14|   |a22  a23  a24|   |a11  a13  a14|
     |             |   |             |   |             |
K3 = |a12  a22  a24| + |a23  a33  a34| + |a13  a33  a34|
     |             |   |             |   |             |
     |a14  a24  a44|   |a24  a34  a44|   |a14  a34  a44|

substitute coefficients
$$I_{1} = 6$$
     |4  2|   |1  1|   |4  2|
I2 = |    | + |    | + |    |
     |2  1|   |1  1|   |2  1|

$$I_{3} = \left|\begin{matrix}4 & 2 & 2\\2 & 1 & 1\\2 & 1 & 1\end{matrix}\right|$$
$$I_{4} = \left|\begin{matrix}4 & 2 & 2 & 1\\2 & 1 & 1 & \frac{1}{2}\\2 & 1 & 1 & \frac{1}{2}\\1 & \frac{1}{2} & \frac{1}{2} & -2\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}- \lambda + 4 & 2 & 2\\2 & - \lambda + 1 & 1\\2 & 1 & - \lambda + 1\end{matrix}\right|$$
     |4  1 |   | 1   1/2|   | 1   1/2|
K2 = |     | + |        | + |        |
     |1  -2|   |1/2  -2 |   |1/2  -2 |

     |4   2    1 |   | 1    1   1/2|   |4   2    1 |
     |           |   |             |   |           |
K3 = |2   1   1/2| + | 1    1   1/2| + |2   1   1/2|
     |           |   |             |   |           |
     |1  1/2  -2 |   |1/2  1/2  -2 |   |1  1/2  -2 |

$$I_{1} = 6$$
$$I_{2} = 0$$
$$I_{3} = 0$$
$$I_{4} = 0$$
$$I{\left(\lambda \right)} = - \lambda^{3} + 6 \lambda^{2}$$
$$K_{2} = - \frac{27}{2}$$
$$K_{3} = 0$$
Because
$$I_{2} = 0 \wedge I_{3} = 0 \wedge I_{4} = 0 \wedge K_{3} = 0 \wedge I_{1} \neq 0$$
then by type of surface:
you need to
then the canonical form of the equation will be
$$I_{1} \tilde x^{2} + \frac{K_{2}}{I_{1}} = 0$$
$$6 \tilde x^{2} - \frac{9}{4} = 0$$
$$\left(\tilde x + 0\right)^{2} = \frac{3}{8}$$
this equation is fora type two parallel planes
- reduced to canonical form