A =    
 
    2.  - 1.    1.    4.  
  - 1.    3.    1.    2.  
    1.    1.    5.  - 3.  
    4.    2.  - 3.    6.  
 
 The P Q and A matrix are ;    
 
    1.    0.        0.        0.      
    0.  - 0.2357    0.2357    0.9428  
    0.    0.2357    0.9550  - 0.1798  
    0.    0.9428  - 0.1798    0.2807  
 
  - 0.2357    0.2357    0.9428  
    0.2357    0.9550  - 0.1798  
    0.9428  - 0.1798    0.2807  
 
    2.        4.2426  - 1.D-16    0.      
    4.2426    3.4444  - 2.2729    2.9293  
  - 1.D-16  - 2.2729    6.2324  - 0.7448  
    0.        2.9293  - 0.7448    4.3232  
 
 The P Q and A matrix are ;    
 
    1.    0.    0.        0.      
    0.    1.    0.        0.      
    0.    0.  - 0.6130    0.7901  
    0.    0.    0.7901    0.6130  
 
  - 0.6130    0.7901  
    0.7901    0.6130  
 
    2.        4.2426    7.D-17  - 9.D-17  
    4.2426    3.4444    3.7077  - 4.D-16  
    7.D-17    3.7077    5.7621  - 1.1097  
  - 9.D-17  - 4.D-16  - 1.1097    4.7934  
 
 The tridiagonal matrix by householder method is :    
 
    2.        4.2426    7.D-17  - 9.D-17  
    4.2426    3.4444    3.7077  - 4.D-16  
    7.D-17    3.7077    5.7621  - 1.1097  
  - 9.D-17  - 4.D-16  - 1.1097    4.7934