Finding Eigenvectors with a Parameter in Homework Solution?

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The discussion centers on finding eigenvalues and eigenvectors for a 3x3 matrix where all entries are 1. The eigenvalues identified are 0 and 3, consistent with the lecturer's findings. However, there is confusion regarding the representation of eigenvectors; textbooks provide them in terms of a parameter, while the lecturer gives specific coordinates. The conversation suggests that any scalar multiple of an eigenvector is also an eigenvector, implying that a parameterized form can encompass all possible eigenvectors. This highlights the flexibility in representing eigenvectors in linear algebra.
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Homework Statement




Okay, we've got a 3x3 matrix. All the entries are equal to 1. Call the matrix A.
Basically It looks like this
1 1 1
1 1 1
1 1 1

find all the eigenvalues and eigenvectors.

The Attempt at a Solution



Right, I got the eigenvalues being 0 and 3, the same as my lecturer got. That's fine, I just let the determinant of (\lambdaI-A) equal 0.
When getting the eigenvectors, every book I read gives the vector in terms of a parameter, such as t. However, my lecturer got vectors with specific coordinates.

What am I supposed to do?
 
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Maybe_Memorie said:

Homework Statement




Okay, we've got a 3x3 matrix. All the entries are equal to 1. Call the matrix A.
Basically It looks like this
1 1 1
1 1 1
1 1 1

find all the eigenvalues and eigenvectors.

The Attempt at a Solution



Right, I got the eigenvalues being 0 and 3, the same as my lecturer got. That's fine, I just let the determinant of (\lambdaI-A) equal 0.
When getting the eigenvectors, every book I read gives the vector in terms of a parameter, such as t. However, my lecturer got vectors with specific coordinates.

What am I supposed to do?

Let v be an eigenvector of your matrix and let l be its eigenvalue. If A is your matrix then, as you know Av = lv. Now, what if you were to take a multiple of v, is that an eigenvector? That is, if k is a scalar, is kv an eigenvector? If so, can you think of a parametrized form of v that would include all multiples of v?
 
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