(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)= _ .

问题描述:

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
)
= ___ .

(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