问题 解答题
(1+
1
2
)(1+
1
4
)(1+
1
6
)…(1+
1
10
)(1-
1
3
)(1-
1
5
)…(1-
1
9
).
答案

(1+

1
2
)(1+
1
4
)(1+
1
6
)…(1+
1
10
)(1-
1
3
)(1-
1
5
)…(1-
1
9
),

═[(1+

1
2
)(1-
1
3
)][(1+
1
4
)(1-
1
5
)]…[(1+
1
8
)(1-
1
9
)](1+
1
10

=1×1×…×1×

11
10

=

11
10

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