A is a 3x3 matrix with two eigenvalues. Each eigenspace is one-dimensional. Is A diagonalizable? Solution FALSE If A is 3x3, its characteristic polynomial is of degree 3 and has 3 roots counting with multiplicities. If there are only 2 eigenvalues, one of them is of multiplicity 2, and the associated eigenspace should be 2-dimensional for A to be diagonalizable..