To determine if matrix \( P \) diagonalizes matrix \( A \), we need to check if \( P^{-1}AP \) is a diagonal matrix. If it is, then \( P \) diagonalizes \( A \).
Step 1: Calculate \( P^{-1} \)
The inverse of matrix \( P \) is calculated as follows:
To determine if \( D \) is a diagonal matrix, we observe its structure. A diagonal matrix has non-zero entries only on its main diagonal. Here, \( D \) has non-zero entries off the diagonal, specifically: