Express the columns of X in equation 9.4 as linear combinations of columns of X∗ in equation 9.15. Also, express the columns of X∗ in equation 9.15 as linear combinations of columns of X. Thus, the...

Express the columns of X in equation 9.4 as linear combinations of columns of X∗ in equation 9.15. Also, express the columns of X∗ in equation 9.15 as linear combinations of columns of X. Thus, the space spanned by columns of X is the same as that spanned by columns of X∗.