  
 The values of N x1 x2 x3 x4 respectively :    
 
    0.    1.5         1.25        1.          0.75      
    1.    1.056454    0.851376    0.684750    0.584436  
    2.    0.979212    0.788578    0.659124    0.568218  
    3.    0.979061    0.788984    0.660975    0.569006  
    4.    0.978892    0.788795    0.660741    0.568901  
    5.    0.978913    0.788819    0.660771    0.568914  
 