(A,E)=
111...11100...00
011...11010...00
001...11001...00
............
000...11000...10
000...01000...01
ri-r(i+1),i=1,2,...,n-1--依次上一行减下一行
100...001-10...00
010...0001-1...00
001...00001...00
............
000...10000...1-1
000...01000...01
所以A^-1=
1-10...00
01-1...00
001...00
......
000...1-1
000...01