题目内容
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
| 1 |
| 128 |
| 1 |
| 256 |
| 1 |
| 512 |
| 1 |
| 1024 |
| 1 |
| 2048 |
| 1 |
| 4096 |
考点:分数的巧算
专题:计算问题(巧算速算)
分析:通过观察,发现从第二项起,每个分数都是前一个分数的
,因此可把每个分数拆成两个分数相减的形式,然后通过加减相互抵消,解决问题.
| 1 |
| 2 |
解答:
解:
+
+
+
+
+
+
+
+
+
+
+
=1-
+
-
+
-
+…+
-
=1-
=
故答案为:
.
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 16 |
| 1 |
| 32 |
| 1 |
| 64 |
| 1 |
| 128 |
| 1 |
| 256 |
| 1 |
| 512 |
| 1 |
| 1024 |
| 1 |
| 2048 |
| 1 |
| 4096 |
=1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 8 |
| 1 |
| 2048 |
| 1 |
| 4096 |
=1-
| 1 |
| 4096 |
=
| 4095 |
| 4096 |
故答案为:
| 4095 |
| 4096 |
点评:此题采用了裂项消项法,先进行分数裂项,然后通过加减相互抵消,求出结果.
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