计算行列式 -a1 a1 0 ...0 0 0 -a2 a2...0 0 .0 0 0.-an an 1 1 1...1 1
问题描述:
计算行列式 -a1 a1 0 ...0 0 0 -a2 a2...0 0 .0 0 0.-an an 1 1 1...1 1
答
-a1 a1 0 ...0 0
0 -a2 a2 ...0 0
.........
0 0 0 ...-an an
1 1 1 ...1 1
把2,3,...,n列都加到第1列,得
0 a1 0 ...0 0
0 -a2 a2 ...0 0
.........
0 0 0 ...-an an
n+1 1 1 ...1 1
按第1列展开
行列式 = (n+1)*(-1)^n * a1a2...an