clear
disp('Matrix-matrix product')
A = [2 4 7; 8 9 10]
pause
B = [2 -1 0;-1 2 -1; 0 -1 2]
pause
AB = A*B
pause
BA = 'not defined'
pause
disp('Column version of matrix-matrix product')
pause
disp('col1 of AB is A times col1 of B')
col1_AB = A*B(:,1)
pause
disp('col2 of AB is A times col2 of B')
col2_AB = A*B(:,2)
pause
disp('col3 of AB is A times col3 of B')
col3_AB = A*B(:,3)
pause
AB = [col1_AB col2_AB col3_AB]
pause
disp('Row operations via elementary matrices')
pause
A = [1 2 1;1 3 2; 1 0 1]
pause
E21 = eye(3)
pause
E21(2, 1) = -1
pause
E31 = eye(3)
pause
E31(3,1) = -1
pause
disp('E21 A = ')
disp(E21*A)
pause
disp('E31 (E21 A)= ')
disp(E31*(E21*A))
pause
disp('(E31 E21) A = ')
disp((E31*E21)*A)