Inversion de la matrice ܲ = ቌ 1 1 1 −1
2 0 1 1
0 1 0 2
−1 21 0
ቍ par la méthode de Gauss-Jordan
ቌ 1 1 1 −1 2 0 1 1
0 1 0 2
−1 21 0
1 0 0 10 0 0 0
0 00 0 1 00 1
ቍ ܮଶ← ܮଶ− ܮଵ
ܮଷ← ܮଶ− 2ܮଵ
ܮସ← ܮସ− ܮଵ
ቌ 1 1 0 −2 0 −2 0 0
0 1 0 1
−1 01 −1
1 0
−1 1
−2 0−1 0
0 00 0 1 00 1
ቍ ܮଷ← ܮଶ− ܮଷ
ቌ 1 1 0 −2 0 0 0 0
0 1 0 1 1 1 1 −1
1 0
−1 1
1 1
−1 0
0 00 0
−1 00 1
ቍ ܮସ← ܮଷ− ܮସ
ቌ 1 1 0 −2 0 0 0 0
0 1 0 1 1 1 0 2
1 0
−1 1 1 1 2 1
0 0 0 0
−1 0−1 −1
ቍ ܮସ←1 2 ܮସ
ۉ ۈۇ1 1
0 −2 0 0 0 0
0 1 0 1 1 1 0 1
1 0
−1 1 1 1 1 1
2
0 0 0 0
−1 0
−1 2 −1
2ی
ۋۊ ܮଵ← ܮଵ− ܮସ
ܮଶ← ܮଶ− ܮସ
ܮଷ← ܮଷ− ܮସ
ۉ ۈۈ ۈۈ ۇ1 1
0 −2 0 0 0 0
0 0 0 0 1 0 0 1
0 −1 2
−2 1
2 0 1 2 1 1 2
12 1 1 2 2 1
2
−1 2 1
2
−1 2 1
2ی ۋۋ ۋۋ ۊ
ܮଶ← −1 2 ܮଶ
ۉ ۈۈ ۈۈ ۇ1 1
0 1 0 0 0 0
0 0 0 0 1 0 0 1
0 −1
2 1 −1 4 0 1
2 1 1 2
1
2 1 2
−1 4 −1
4
−1 2 1
2
−1 2 1
2 ی ۋۋ ۋۋ ۊ
ܮଵ← ܮଵ− ܮଶ
ۉ ۈۈ ۈۈ ۇ1 0
0 1 0 0 0 0
0 0 0 0 1 0 0 1
−1 −1 4 1 −1 4 0 1
2 1 1 2
34 3 4
−1 4 −1
4
−1 2 1
2
−1 2 −1
2 ی ۋۋ ۋۋ ۊ
Conclusion : la matrice ܲ est inversible et son inverse est : ܲିଵ= ۉ ۈۈ
ۇ−1 −ଵସ 1 −ଵସ 0 ଵଶ 1 ଵଶ
ଷ ସ ଷସ
−ଵସ −ଵସ
−ଵଶ ଵଶ
−ଵଶ −ଵଶی ۋۋ ۊ=ଵସቌ
−4 −1
4 −1
0 2 4 2
3 3
−1 −1
−2 2
−2 −2 ቍ
Vérification : ܲିଵ× ܲ =ଵସቌ
−4 −1
4 −1
0 2 4 2
3 3
−1 −1
−2 2
−2 −2 ቍ ቌ
1 1 1 −1
2 0 1 1
0 1 0 2
−1 21 0 ቍ =ଵସቌ
4 00 4 0 00 0
0 0 0 0 4 00 4
ቍ = ܫ