Consider the matrix P =Which one of the following statements

Consider the matrix P =

Which one of the following statements about P is INCORRECT?

1. Determinant of P is equal to 1.
2. P is orthogonal.
3. Inverse of P is equal to its transpose.
4. All eigenvalues of P are real numbers.

The eigenvalues of an orthogonal matrix are of magnitude 1 and are real (s) complex conjugate pairs.