题目内容
(2012•深圳二模)无限循环小数可以化为有理数,如0.
=
,0.
=
,0.
1
=
,…,请你归纳出0.0
=
(表示成最简分数
,n,m∈N*.
| • |
| 1 |
| 1 |
| 9 |
| • |
| 1 |
| • |
| 3 |
| 13 |
| 99 |
| • |
| 0 |
| • |
| 5 |
| 5 |
| 333 |
| • |
| 1 |
| • |
| 7 |
| 17 |
| 990 |
| 17 |
| 990 |
| m |
| n |
分析:由题意,0.0
=0.017+0.00017+…+0.0000017+…,利用等比数列的求和公式,取极限,即可得到结论.
| • |
| 1 |
| • |
| 7 |
解答:解:由题意,0.0
=0.017+0.00017+…+0.0000017+…=
∴当n→+∞时,0.0
=
=
故答案为:
.
| • |
| 1 |
| • |
| 7 |
| 0.017(1-0.01n) |
| 1-0.01 |
∴当n→+∞时,0.0
| • |
| 1 |
| • |
| 7 |
| 0.017 |
| 1-0.01 |
| 17 |
| 990 |
故答案为:
| 17 |
| 990 |
点评:本题考查类比推理,考查等比数列的求和,考查极限思想,属于基础题.
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