[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)]+…+[1/1999+(-1/2000)]=?等于多少啊?A.2000/1999 B.1999/2000 C.1/2000 D.1/1999

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[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)]+…+[1/1999+(-1/2000)]=?等于多少啊?A.2000/1999 B.1999/2000 C.1/2000 D.1/1999
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[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)]+…+[1/1999+(-1/2000)]=?等于多少啊?A.2000/1999 B.1999/2000 C.1/2000 D.1/1999
[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)]+…+[1/1999+(-1/2000)]=?等于多少啊?
A.2000/1999 B.1999/2000 C.1/2000 D.1/1999

[1+(-1/2)]+[1/2+(-1/3)]+[1/3+(-1/4)]+…+[1/1999+(-1/2000)]=?等于多少啊?A.2000/1999 B.1999/2000 C.1/2000 D.1/1999
B
你把中括号全部去掉就成了下面的式子,(-1/2)+1/2=0,(-1/3)+1/3=0,以此类推,就得到
1+(-1/2)+1/2+(-1/3)+1/3+(-1/4)+…+1/1999+(-1/2000)=1-(1/2000)=1999/2000