function []=prob_6_4_27(A)
% 
%
% Written by:
% -- 
% John L. Weatherwax                2006-11-21
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

format long

A = [ 1 1 1 1 1 ; 1 2 3 4 5 ];
disp( '>>>>> A^T * A is' ); 
(A.')*A
disp( '>>>>> this matrix is singular ... selecting linearly independent columns gives' );
A = A(:,1:2)
disp( '>>>>> now P is' );
P = A*inv((A.')*A)*(A.')
disp( '>>>>> the requested eig call returns' );
[S,LAMBDA] = eig(P)
(S.') * S