(1-1/2)x(1+1/2)x(1-1/3)x(1+1/3)x.x(1-1/99）x(1+1/99)结果是等于50/9
3个回答
如果自己接受不了,可就先别算那么长,一节节算算,找找规律
(1-1/2) X (1+1/2) X (1-1/3) X (1+1/3)
= 1/2 X 3/2 X 2/3 X 4/3
= 1/2 X 1 X 4/3
= 2/3
(1-1/2) X (1+1/2) X (1-1/3) X (1+1/3) X (1-1/4) X (1+1/4)
= 1/2 X 3/2 X 2/3 X 4/3 X 3/4 X 5/4
= 1/2 X 1 X 1 X 5/4
= 5/8
同理,题目就是
(1-1/2) X (1+1/2) X (1-1/3) X …… X (1+1/98) X (1-1/99) X (1+1/99)
= 1/2 X 3/2 X 2/3 X …… X 99/98 X 98/99 X 100/99
= 1/2 X 1 X 1 X …… X 1 X 100/99
= 50/99
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