题目内容
已知|ab-2|+|a-2|=0,求| 1 |
| ab |
| 1 |
| (a+1)(b+1) |
| 1 |
| (a+2)(b+2) |
| 1 |
| (a+2008)(b+2008) |
分析:先根据非负数的性质求出a、b的值,再代入
+
+
+…+
,拆分抵消即可求解.
| 1 |
| ab |
| 1 |
| (a+1)(b+1) |
| 1 |
| (a+2)(b+2) |
| 1 |
| (a+2008)(b+2008) |
解答:解:∵|ab-2|+|a-2|=0,
∴
,
解得
.
∴
+
+
+…+
=
+
+
+…+
=1-
=
.
∴
|
解得
|
∴
| 1 |
| ab |
| 1 |
| (a+1)(b+1) |
| 1 |
| (a+2)(b+2) |
| 1 |
| (a+2008)(b+2008) |
=
| 1 |
| 1×2 |
| 1 |
| 2×3 |
| 1 |
| 3×4 |
| 1 |
| 2009×2010 |
=1-
| 1 |
| 2010 |
=
| 2009 |
| 2010 |
点评:考查了非负数的性质:绝对值和分式的化简求值,注意
=
-
.
| 1 |
| n(n+1) |
| 1 |
| n |
| 1 |
| n+1 |
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