Find the eigenvalues and eigenvectors of the matrix M , where M{2,2} = (1/2 2/3 ; 1/2 1/3) Hence express M in the form PDP^-1 where D is a diagonal matrix.

To start off, It's worth noting the definition of eigenvalues: for a Matrix A (n x n), it's ith eigenvalue (λi) is defined as the scalar constant the ith eigenvector (vi) is multiplied for the matrix multiplication Avi : Avi = λiv (1)Hence, to find the ith eigenvalues, rearrange to get the equation: (A - λiIn)vi = 0 (2)Where In is the n x n Identity Matrix.For a non-trivial solution, A-λiIi must be defined such that det(A-λiIi) = 0Now we can solve the equation for λ:(1/2 - λ)(1/3 - λ) - (1/2)(2/3) = 0 (3)-The characteristic equation for A, with roots λ = 1, -1/6Now substitute each λi into equation (2) to solve for vi where vi = (xi ; yi).vi should have no particular solution; there should be an infinite family of solutions. If this is not the case, an error has been made. Therefore, the eigenvector can take any value of x and y, with the ration of x : y constant. To solve, set the value of xi (e.g. xi = 1), then solve for yi (or vice versa).Finally, the matrix D is the diagonal matrix of entries λi, and P the matrix of eigenvectors (be consistent with the order the ith eigenvalues and eigenvectors are entered):A = PDP-1 (4)

LT

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