利用因式分解计算:(1−1/22)(1−1/32)(1−1/42)…(1−1/92)(1−1/102).

问题描述:

利用因式分解计算:(1−

1
22
)(1−
1
32
)(1−
1
42
)…(1−
1
92
)(1−
1
102
).

原式=(1-

1
2
)(1+
1
2
)(1-
1
3
)(1+
1
3
)(1-
1
4
)(1+
1
4
)…(1-
1
9
)(1+
1
9
)(1-
1
10
)(1+
1
10

=
1
2
×
3
2
×
2
3
×
4
3
×
3
4
×
5
4
…×
8
9
×
10
9
×
9
10
×
11
10

=
1
2
×
11
10

=
11
20