Find the eigenvalues and associated unit eigenvectors of the symmetric matrix The smaller eigenvalue has associated unit eigenvector .The larger eigenvalue has associated unit eigenvector .Note: The eigenvectors above form an orthonormal eigenbasis for the column space of .

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?