(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+
)×(1-1 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 99
答
(1+
)×(1-1 2
)×(1+1 2
)×(1-1 3
)×…×(1+1 3
)(1-1 99
),1 99
=(1-
)×(1+1 2
)×(1-1 2
)×(1+1 3
)×…×(1-1 3
)(1+1 99
),1 99
=
×1 2
×3 2
×2 3
×…×4 3
×98 99
,100 99
=
×1 2
,100 99
=
.50 99