|1/21-1/20|+|1/22-1/21|+|1/23-1/22|+...+|1/2004-1/2003|
-23-22-21-20-19.-1=?
|1/21-1/20|+|1/22-1/21|+|1/23-1/22|+...|1/30-1/29| 急
关于绝对值|1/21-1/20|+|1/22-1/21|+|1/23-1/22|+...|1/30-1/29|
|1/21-1/20|+|1/22-1/21|+|1/23-1/22|+…+|1/30-1/29|
计算:|1/21-1/20|+|1/22-1/21|+|1/23-1/22|...|1/30-1/29|
1/(1/20+1/21+1/22+1/23+...+1/38+1/39)
简算:23×21/22+1/22
23×22分之21+22分之1
(1-1/19)(1-1/20)(1-1/21)(1-1/22)...(1-1/99)=
[(-1)^2003=(-1)2004-10]*22
(19/1-1)(20/1-1)(21/1-1)(22/1)...(99/1-1)
20*21分之1+21*22分之1+22*23分之1+.49*50分之1 用简便算法计算