问题
解答题
用简便方法计算 (1)20102-2011×2009 (2)(1-
|
答案
(1)原式=20102-(2010+1)
=20102-(20102-1)
=20102-20102+1
=1;
(2)原式=(1-
)(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 10
=
×1 2
×3 2
×2 3
×4 3
×3 4
×…×5 4
×8 9
×9 10 11 10
=
×1 2 11 10
=
.11 20