2-r1、r3-r1、...、rn-r1
Dn=|a1+1 a2 a3 ... an|
-1 2 0 ... 0
-1 0 3 ... 0
..................
-1 0 0 ... n
=|w a2 a3 .... an| 【c1+c2/2+c3/3+...+cn/n
0 2 0 .... 0 w=1+a1+a2/2+...+an/n 】
0 0 3 .... 0
................
0 0 0 .... n 《上三角》
=w**n!
=n!*(1+∑ak/k) 【k=1 to n】