(1+12)×(1-12)×(1+13)×(1-13)×(1+14)×(1-14)×…×(1+199)×(1-199)×(1+1100)×(1-1100)
问题描述:
(1+
)×(1-1 2
)×(1+1 2
)×(1-1 3
)×(1+1 3
)×(1-1 4
)×…×(1+1 4
)×(1-1 99
)×(1+1 99
)×(1-1 100
)1 100
答
(1+12)×(1-12)×(1+13)×(1-13)×(1+14)×(1-14)×…×(1+199)×(1-199)×(1+1100)×(1-1100),=(1-12)×[(1+12)×(1-13)]×[(1+13)×(1-14)]×…×[(1+199)×(1-1100)]×(1+11...
答案解析:通过仔细观察,发现:(1+
)×(1-1 2
)=1,(1+1 3
)×(1-1 3
)=1,…,(1+1 4
)×(1-1 99
)=1,最后剩下(1-1 100
)和(1+1 2
),解决问题.1 100
考试点:分数的巧算.
知识点:解答此题,应认真观察,根据数字特点,运用运算技巧,灵活解答.