题目内容
计算:(
+
+
+…+
)(
+1).
| 1 | ||
|
| 1 | ||||
|
| 1 | ||||
|
| 1 | ||||
|
| 2009 |
(
+
+
+…+
)(
+1)
=(
-1+
-
+…+
-
)(
+1)
=(
+1)(
-1)
=2009-1
=2008.
| 1 | ||
|
| 1 | ||||
|
| 1 | ||||
|
| 1 | ||||
|
| 2009 |
=(
| 2 |
| 3 |
| 2 |
| 2009 |
| 2008 |
| 2009 |
=(
| 2009 |
| 2009 |
=2009-1
=2008.
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