Eigenvalues and Eigenvectors of a 2x2 Matrix P

SherlockOhms
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Homework Statement


Find the eigenvalues and eigenvectors of P = {(0.8 0.6), (0.2 0.4)}. Express {(1), (0)} and {(0), (1)} as sums of eigenvectors.



Homework Equations


Row ops and det(P - λI) = 0.


The Attempt at a Solution


I've found the eigenvectors and eigenvalues of P to be 1 with t{(3), (1)} and 0.2 with q{(-1), (1)} were t and q are arbitrary (parameters). How do I express the two other vectors (in the question statement) as sums of eigenvectors? Thanks.
 
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Unless there's another condition you need to satisfy, you can take t=q=1, so the problem is asking you now to solve
$$\begin{pmatrix} 1 \\ 0 \end{pmatrix} = a\begin{pmatrix} 3 \\ 1 \end{pmatrix}+b\begin{pmatrix} -1 \\ 1 \end{pmatrix}$$ which is just a system of two equations and two unknowns. And then do the same thing for the other vector.
 
Cool. Got it now. Thanks!
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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