计算:[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)+…[1/1999+(-21/2000)]A 2000_数学解答

计算:[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)+…[1/1999+(-21/2000)]
A 2000/1999 B 1999/2000C 1/2000D 1/1999
sorry，错了，是[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)+…+[1/1999+(-1/2000)]

人气：160 ℃　时间：2020-01-28 18:41:09

解答

:[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)+…[1/1999+(-21/2000)]
=1-1/2+1/2-1/3+1/3-1/4+.+1/1999-1/2000
=1-1/2000
=1999/2000
选B