28 lines
1.5 KiB
Text
28 lines
1.5 KiB
Text
(%i1) eqns: [ 2*w-x+5*y+z=-3, 3*w+2*x+2*y-6*z=-32, w+3*x+3*y-z=-47, 5*w-2*x-3*y+3*z=49];
|
|
(%o1) [z + 5 y - x + 2 w = - 3, (- 6 z) + 2 y + 2 x + 3 w = - 32,
|
|
(- z) + 3 y + 3 x + w = - 47, 3 z - 3 y - 2 x + 5 w = 49]
|
|
(%i2) A: augcoefmatrix (eqns, [w,x,y,z]);
|
|
[ 2 - 1 5 1 3 ]
|
|
[ ]
|
|
[ 3 2 2 - 6 32 ]
|
|
(%o2) [ ]
|
|
[ 1 3 3 - 1 47 ]
|
|
[ ]
|
|
[ 5 - 2 - 3 3 - 49 ]
|
|
(%i3) C: coefmatrix(eqns, [w,x,y,z]);
|
|
[ 2 - 1 5 1 ]
|
|
[ ]
|
|
[ 3 2 2 - 6 ]
|
|
(%o3) [ ]
|
|
[ 1 3 3 - 1 ]
|
|
[ ]
|
|
[ 5 - 2 - 3 3 ]
|
|
(%i4) c[n]:= (-1)^(n+1) * determinant (submatrix (A,n))/determinant (C);
|
|
n + 1
|
|
(- 1) determinant(submatrix(A, n))
|
|
(%o4) c := ---------------------------------------
|
|
n determinant(C)
|
|
(%i5) makelist (c[n],n,1,4);
|
|
(%o5) [2, - 12, - 4, 1]
|
|
(%i6) linsolve(eqns, [w,x,y,z]);
|
|
(%o6) [w = 2, x = - 12, y = - 4, z = 1]
|