What is mean of the positive-definite symmetric matrix? Given a positive-definite sym- metric matrix A, explain how to find its largest eigenvector (Suggest: using pca" or "eig in matlab). Give an example of principal component analysis (PCA) with N variables X1, ... , Xn to find one "common factor. What is mean of the positive-definite symmetric matrix? Given a positive-definite sym- metric matrix A, explain how to find its largest eigenvector (Suggest: using pca" or "eig in matlab). Give an example of principal component analysis (PCA) with N variables X1, ... , Xn to find one "common factor