1. The problem statement, all variables and given/known data I think my teacher made a mistake in his homework answer. I need to verify this for practice. The answer I got is below. The answer the teacher has is in the pdf. 2. Relevant equations Please refer to attached pdf 3. The attempt at a solution So there is two eigenvalues= 4 and 2 but the eigenvalue 2 has 2 eigenvectors [-1 1 0]T and [0 0 1]T but my teacher has only one [-1 1 0]T. That's why he says A is not diagonalizable. Do you think it's correct?