题目内容
观察下列等式:
=
=
-
,
=
=
-
,请你从上述等式中找出规律,并利用这一规律计算(
+
+
+…+
)•(
+
)=______.
| 1 | ||||
|
(
| ||||||||
(
|
| 3 |
| 2 |
| 1 | ||||
|
(
| ||||||||
(
|
| 4 |
| 3 |
| 2 | ||||
|
| 2 | ||||
|
| 2 | ||||
|
| 2 | ||||
|
| 2012 |
| 2 |
原式=2(
-
+
-
+
-
+…+
-
)(
+
)
=2(
-
)(
+
)
=2×2010=4020.
故答案为:4020.
| 3 |
| 2 |
| 4 |
| 3 |
| 5 |
| 4 |
| 2012 |
| 2011 |
| 2012 |
| 2 |
=2(
| 2012 |
| 2 |
| 2012 |
| 2 |
=2×2010=4020.
故答案为:4020.
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