Consider the linear system yâ â²=Ayâ , where A is a real 2Ã2 constant matrix with repeated eigenvalues. Use the given information to determine the matrix A. Phase plane solution trajectories have horizontal tangents on the line y2=2y1 and vertical tangents on the line y1=0. The matrix A has a nonzero repeated eigenvalue and a21=â6.

Respuesta :

Answer:

[tex]A = \left[\begin{array}{ccc}1&0\\-2&1\end{array}\right][/tex]

Step-by-step explanation:

A is a 2 x 2 coefficient matrix with repeated eigenvalues

[tex]A = \left[\begin{array}{ccc}a_{11} &a_{12} \\a_{21} &a_{22} \end{array}\right][/tex]  

The linear equation is given by the relationship y' = Ay

[tex]\left[\begin{array}{ccc}y_{1}\\y_{2} \end{array}\right]' = \left[\begin{array}{ccc}a_{11} &a_{12} \\a_{21} &a_{22} \end{array}\right] + \left[\begin{array}{ccc}y_{1}\\y_{2} \end{array}\right][/tex]

[tex]y_{1}' = a_{11}y_{1} + a_{12}y_{2}\\[/tex]...............(1)

[tex]y_{2}' = a_{21}y_{1} + a_{22}y_{2}[/tex]................(2)

Vertical tangents on the line, [tex]y_{1} = 0[/tex]  

[tex]y_{1}' = a_{11}y_{1} + a_{12}y_{2} = 0[/tex]

[tex]a_{12} y_{2} = 0[/tex], [tex]a_{12} = 0[/tex]

[tex]a_{21} = -6[/tex], [tex]y_{2} = 2y_{1}[/tex]

[tex]y_{2}' = a_{21}y_{1} + a_{22}y_{2} = 0[/tex]...........(2)

Substitute these values into equation (2)

[tex]-6y_{1} + a_{22}(2y_{1}) = 0\\(-3 + a_{22})y_{1} = 0\\ y_{1} =0\\ -3 + a_{22} = 0\\a_{22} = 3[/tex]

[tex]A = \left[\begin{array}{ccc}3&0\\-6&3\end{array}\right][/tex]

[tex]A = \left[\begin{array}{ccc}1&0\\-2&1\end{array}\right][/tex]