Find the eigenvalues and eigenvectors of A geometrically over the real numbers ℝ. (If an eigenvalue does not exist, enter DNE. If an eigenvector does not exist, enter DNE in any single blank.) A = 0 1 1 0 (reflection in the line y = x) λ1 = has eigenspace span (smaller λ-value) λ2 = has eigenspace span (larger λ-value)

Respuesta :

Answer:

∴The eigen values are -1,1.

The eigen vector for 1 is    [tex]\left[\begin{array}{c}1\\-1\end{array}\right][/tex] .

The eigen vector for [tex]\lambda[/tex]= - 1 is    [tex]\left[\begin{array}{c}1\\1\end{array}\right][/tex] .

Step-by-step explanation:

Given matrix is

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

To find the eigen values of the given matrix, we set

[tex]det(A-\lambda I)=0[/tex]

[tex]\left|\begin{array}{cc}0&1\\1&0\end{array}\right|- \lambda \left|\begin{array}{cc}1&0\\0&1\end{array}\right|=0[/tex]

[tex]\left|\begin{array}{cc}0&1\\1&0\end{array}\right|- \left|\begin{array}{cc} \lambda&0\\0& \lambda\end{array}\right|=0[/tex]

[tex]\left|\begin{array}{cc} -\lambda&1\\1& -\lambda\end{array}\right|=0[/tex]

[tex]\Rightarrow \lambda^2-1=0[/tex]

[tex]\Rightarrow \lambda^2=1[/tex]

[tex]\Rightarrow \lambda=\pm1[/tex]

∴The eigen values are -1,1.

For [tex]\lambda=1[/tex]

Let the eigen vector for [tex]\lambda=1[/tex] is

[tex]v_1=\left[\begin{array}{c}x_1\\x_2\end{array}\right][/tex]

∴[tex](A-\lambda I)v_1=O[/tex]

[tex]\left[\begin{array}{cc} 1&1\\1&1\end{array}\right] \left[\begin{array}{c}x_1\\x_2\end{array}\right]=O[/tex]

[tex]\Rightarrow \left[\begin{array}{c}x_1+x_2\\x_1+x_2\end{array}\right]=O[/tex]

[tex]\therefore x_1+x_2=0[/tex]

[tex]\Rightarrow x_2=-x_1[/tex]

let [tex]x_1=1[/tex]

[tex]\therefore x_2=-1[/tex]

The eigen vector for 1 is    [tex]\left[\begin{array}{c}1\\-1\end{array}\right][/tex] .

For [tex]\lambda=-1[/tex]

Let the eigen vector for [tex]\lambda=1[/tex] is

[tex]v_2=\left[\begin{array}{c}x_3\\x_4\end{array}\right][/tex]

∴[tex](A-\lambda I)v_2=O[/tex]

[tex]\left[\begin{array}{cc} -1&1\\1&-1\end{array}\right] \left[\begin{array}{c}x_3\\x_4\end{array}\right]=O[/tex]

[tex]\Rightarrow \left[\begin{array}{c}-x_3+x_4\\x_3-x_4\end{array}\right]=O[/tex]

[tex]\therefore- x_3+x_4=0[/tex]

and

[tex]\therefore x_3-x_4=0[/tex]

From the above equations, we get

[tex]x_3=x_4[/tex]

Let [tex]x_3=1[/tex]

Then, [tex]x_4=1[/tex]

The eigen vector for [tex]\lambda[/tex]= - 1 is    [tex]\left[\begin{array}{c}1\\1\end{array}\right][/tex] .

We want to find the eigenvalues and eigenvectors of the given matrix.

The eigenvalues are 1 and -1 and the correspondent eigenvectors are:

[tex]\frac{1}{\sqrt{2} } \left[\begin{array}{ccc}1\\-1\end{array}\right][/tex]  and  [tex]\frac{1}{\sqrt{2} } \left[\begin{array}{ccc}1\\1\end{array}\right][/tex]

We have the matrix:

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

To find the eigenvalues λ, we need to solve:

[tex]det (A - I*\lambda) = det(\left[\begin{array}{ccc}- \lambda &1\\1&-\lambda\end{array}\right]) = 0[/tex]

This gives:

[tex]\lambda^2 - 1 = 0\\\\\lambda = \pm 1[/tex]

Then the eigenvalues are 1 and -1

Now let's get the eigenvectors.

For λ = 1 we must solve:

[tex]\left[\begin{array}{ccc}-1&1\\1&-1\end{array}\right]*\left[\begin{array}{ccc}a\\b\end{array}\right] = 0\\\\\left[\begin{array}{ccc}-1&1\\1&-1\end{array}\right]*\left[\begin{array}{ccc}a\\b\end{array}\right] = \left[\begin{array}{ccc}-a+b\\a-b\end{array}\right] = 0[/tex]

Then a = -b

This eigenvector is:

[tex]\frac{1}{\sqrt{2} } \left[\begin{array}{ccc}1\\-1\end{array}\right][/tex]

(the factor is for normalization)

We do the same thing for the other eigenvalue:

[tex]\left[\begin{array}{ccc}1&1\\1&1\end{array}\right]*\left[\begin{array}{ccc}a\\b\end{array}\right] = 0\\\\\left[\begin{array}{ccc}1&1\\1&1\end{array}\right]*\left[\begin{array}{ccc}a\\b\end{array}\right] = \left[\begin{array}{ccc}a+b\\a+b\end{array}\right] = 0[/tex]

Now we have a = b

[tex]\frac{1}{\sqrt{2} } \left[\begin{array}{ccc}1\\1\end{array}\right][/tex]

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