题目内容
| 4 |
| 3 |
| 4 |
| 9 |
| 4 |
| 27 |
| 4 |
| 81 |
| 4 |
| 243 |
| 4 |
| 729 |
| 1456 |
| 729 |
| 1456 |
| 729 |
分析:通过观察,每个分数的分子都是4,因此,先把4提出来,原式变为(
+
+
+
+
+
)×4,设S=
+
+
+
+
+
①,则3S=1+
+
+
+
+
②.然后求出
+
+
+
+
+
的值,进一步解决问题.
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 729 |
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 729 |
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 729 |
解答:解:S=
+
+
+
+
+
①,
则3S=1+
+
+
+
+
②,
②-①得:
2S=1-
=
,
S=
;
则
+
+
+
+
+
,
=(
+
+
+
+
+
)×4,
=
×4,
=
.
故答案为:
.
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 729 |
则3S=1+
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
②-①得:
2S=1-
| 1 |
| 729 |
| 728 |
| 729 |
S=
| 364 |
| 729 |
则
| 4 |
| 3 |
| 4 |
| 9 |
| 4 |
| 27 |
| 4 |
| 81 |
| 4 |
| 243 |
| 4 |
| 729 |
=(
| 1 |
| 3 |
| 1 |
| 9 |
| 1 |
| 27 |
| 1 |
| 81 |
| 1 |
| 243 |
| 1 |
| 729 |
=
| 364 |
| 729 |
=
| 1456 |
| 729 |
故答案为:
| 1456 |
| 729 |
点评:解答这种类型的题目,应认真观察,运用运算技巧或运算定律,灵活进行简算.
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