Rotation around an axis

Let T:R3R3 be the linear transformation that rotates counterclockwise around the z-axis by 2π3.

  1. Write the matrix for T with respect to the standard basis {[100],[010],[001]}.
  2. Write the matrix for T with respect to the basis {[32120],[010],[001]}.
  3. Determine all (complex) eigenvalues of T.
  4. Is T diagonalizable over C? Justify your answer.