Akm = {{0, 0, (2/5)*(Ee) + (3/5)*(Et2)} , 
       {4, 0, (21/10)*(Ee + (-1)*(Et2))} , 
       {4,-4, (3/2)*((sqrt(7/10))*(Ee + (-1)*(Et2)))} , 
       {4, 4, (3/2)*((sqrt(7/10))*(Ee + (-1)*(Et2)))} }