What if the orthogonal matrix of graduate mathematics is not unique?
The orthogonal matrix of postgraduate mathematics is not only correct. When finding the eigenvector of each eigenvalue, it is required to solve the corresponding homogeneous linear equations. However, the basic solution system of the equations is not unique. According to the assignment of free unknowns, the feature vectors can be different. By constructing orthogonal matrices of different eigenvectors, different orthogonal matrices can be obtained.