Practice Problems

The matrix
  ⁣A‾=[5−6−6−1423−6−4]\ul{A} = \begin{bmatrix} 5 & -6 & - 6 \\ -1 & 4 & 2 \\ 3 & -6 & -4 \end{bmatrix}

has characteristic polynomial
CA(x)=x3−5x2+8x−4=(x−1)(x−2)2C_{A}(x) = x^3 - 5x^2 + 8x - 4 = (x-1)(x-2)^2.

  1. Give the eigenvalues of A‾\A, then
  2. determine their algebraic and geometric multiplicity;
  3. finally,
  4. determine whether or not A‾\A is diagonalizable, and
  5. if it is, give the matrices P ⁣‾ \matP and D ⁣‾ \D, such that   ⁣A‾=P ⁣‾  D ⁣‾  P−1\ul{A} = \matP \, \D \, \minv{P} .

If λ1≤λ2≤λ3\lambda_1 \leq \lambda_2 \leq \lambda_3 (i.e. if we order the eigenvalues from the lowest value to highest value), then:
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