> with(linalg):
> A:=matrix(4,4,[[624,-322, 0, 0], [-322, 552, -322, 41], [ 0, -322,
> 624, -322], [0, 41, -322, 276]]);

                      [ 624    -322       0       0]
                      [                            ]
                      [-322     552    -322      41]
                 A := [                            ]
                      [   0    -322     624    -322]
                      [                            ]
                      [   0      41    -322     276]

# 
> a:=vector([5,5,15,5]);

                          a := [5, 5, 15, 5]

# 
> Y:=linsolve(A,a);

                  [6849287   6380687   16853877  4591055]
             Y := [--------, --------, --------, -------]
                  [32958532  16479266  32958532  8239633]

# 
> y[2]:=evalf(Y[1]);  y[3]:=evalf(Y[2]);  y[4] :=evalf(Y[3]); 
> y[5]:=evalf(Y[4]);

                         y[2] := 0.2078152935


                         y[3] := 0.3871948544


                         y[4] := 0.5113661312


                         y[5] := 0.5571916856

> 
> 
