1/(12×13)+1/(13×14)+……+1/(19×20)的值为:
来源:百度知道 编辑:UC知道 时间:2024/05/28 12:13:16
1/(12×13)+1/(13×14)+……+1/(19×20)的值为:
A.1/12 B.1/20 C.1/30 D.1/40
需求步骤,一道公考题,谢谢!
A.1/12 B.1/20 C.1/30 D.1/40
需求步骤,一道公考题,谢谢!
1/(12×13)+1/(13×14)+……+1/(19×20)
=(1/12-1/13)+(1/13-1/14)+……+(1/19-1/20)
=1/12-1/20
=2/60
=1/30
选C
c
1/12-1/20=1/30
1/(12*13)=1/12-1/13,消去中间向即可
因为:1/(12×13)=1/12-1/13 1/(13×14)=1/13-1/14。。。。。。。1/(19×20)=1/19-1/20
也就是原式=1/12-1/13+1/13-1/14+1/14-1/15+1/15-1/16+1/16-1/17+1/17-1/18+1/18-1/19+1/19-1/20=1/12-1/20=1/30
所以答案为C
1/(12×13)+1/(13×14)+1/(14×15)。。。+1/(19×20)=?
1/(12×13)+1/(13×14)+……+1/(19×20)=???
已知1-1/2=1/2 1/2-1/3=1/6 1/3-1/4=1/12 那么1/6-1/7=()1/12-1/13=()1/2+1/6+1/12=()
公务员题1/(12*13)+1/(13*14)+1/(14*15)+.......+1/(19*20)
1/11+1/12+1/13+1/14+1/15=?
.表达式DateDiff(“y”,#12/30/1999#,#1/13/2000#)的结果是
1/(12×13)+1/(13×14)+……+1/(19×20)的值为多少?是如何计算的?
1/12*13+1/13*14+.......+1/19*20
1/8=1/( )+1/( )1 1/10=1/( )+1/( )1/12=1/( )+1/( )+1/( )
比较大小:1/11+1/29 1/12+1/25 1/13+1/21 1/14+1/19