早教吧 育儿知识 作业答案 考试题库 百科 知识分享

(1+12)×(1-12)×(1+13)×(1-13)×…×(1+199)×(1-199)×(1-12)×(1+13)×(1-13)×…×(1+199)×(1-199)=.

题目详情
1+
1
2
)×(1-
1
2
)×(1+
1
3
)×(1-
1
3
)×…×(1+
1
99
)×(1-
1
99
(1-
1
2
(1+
1
3
(1-
1
3
)×…×(1+
1
99
(1-
1
99
)= ___ .
▼优质解答
答案和解析
(1+
1
2
)×(1-
1
2
)×(1+
1
3
)×(1-
1
3
)×…×(1+
1
99
)(1-
1
99
),
=(1-
1
2
)×(1+
1
2
)×(1-
1
3
)×(1+
1
3
)×…×(1-
1
99
)(1+
1
99
),
=
1
2
×
3
2
×
2
3
×
4
3
×…×
98
99
×
100
99

=
1
2
×
100
99

=
50
99