行列式怎么算?

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行列式怎么算?
行列式怎么算?

行列式怎么算?
(1)Dn
(从第一行起前一行减后一行)=
1-n 1 1 ...1 1
1 1-n 1 ...1 1
1 1 1-n ...1 1
.
2 3 4 ...n 1
(各列加到第一列)=
0 1 1 ...1 1
0 1-n 1 ...1 1
0 1 1-n ...1 1
.
(n+1)n/2 3 4...n 1
=(-1)^(n+1)*(n+1)n/2*
1 1 ...1 1 .
1-n 1 ...1 1
.
1 1 ...1 1
1 1 ...1-n 1
=(-1)^(n+1)*(n+1)n/2*
1 1 ...1 1
-n 0 ...0 0
0 -n ...0 0
.
0 0 ...-n 0
=(-1)^(n+1)*(n+1)n/2*(-1)^(1+n-1)*(-1)^(n-1)*n^(n-2)
=(-1)^n*(n+1)n^(n-1)/2
(2)Dn=(a1*a2*...*a(n+1))^n*V(b1/a1,b2/a2,...,b(n+1)/a(n+1))
=(a1*a2*...*a(n+1))^n*∑[1≤i