问题
解答题
探究性问题:
试用上面规律解决下面的问题: (1)计算
(2)已知
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答案
根据已知的三个等式,总结规律得
=1 n(n+1)
-1 n
,1 n+1
(1)原式=
+1 (x+1)(x+2)
+1 (x+2)(x+3) 1 (x+3)(x+4)
=
-1 x+1
+1 x+2
-1 x+2
+1 x+3
-1 x+3
=1 x+4
-1 x+1
=1 x+4
;3 (x+1)(x+4)
(2)由
+(ab-2)2=0得:a-1=0且ab-2=0,a-1
解得a=1且ab=2,
所以b=2,
则原式=
+1 ab
+…+1 (a+1)(b+1)
,1 (a+2010)(b+2010)
=
+1 1×2
+…+1 2×3
,1 2011×2012
=1-
+1 2
-1 2
+1 3
-1 3
+…+1 4
-1 2010
+1 2011
-1 2011
=1-1 2012
=1 2012
.2011 2012
故答案为:
-1 n
.1 n+1