题目内容
计算:
+(
+
)+(
+
+
)+(
+
+
+
)+…+(
+
+
+
+…+
)=
| 1 |
| 2 |
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 4 |
| 2 |
| 4 |
| 3 |
| 4 |
| 1 |
| 5 |
| 2 |
| 5 |
| 3 |
| 5 |
| 4 |
| 5 |
| 1 |
| 49 |
| 2 |
| 49 |
| 3 |
| 49 |
| 4 |
| 49 |
| 48 |
| 49 |
588
588
.分析:先计算同分母分数,发现是公差为
的一组数列,根据高斯求和公式计算即可求解.
| 1 |
| 2 |
解答:解:
+(
+
)+(
+
+
)+(
+
+
+
)+…+(
+
+
+
+…+
),
=
+1+1
+2+…+24,
=(
+24)×48÷2,
=588.
故答案为:588.
| 1 |
| 2 |
| 1 |
| 3 |
| 2 |
| 3 |
| 1 |
| 4 |
| 2 |
| 4 |
| 3 |
| 4 |
| 1 |
| 5 |
| 2 |
| 5 |
| 3 |
| 5 |
| 4 |
| 5 |
| 1 |
| 49 |
| 2 |
| 49 |
| 3 |
| 49 |
| 4 |
| 49 |
| 48 |
| 49 |
=
| 1 |
| 2 |
| 1 |
| 2 |
=(
| 1 |
| 2 |
=588.
故答案为:588.
点评:考查了分数的巧算,本题先计算同分母分数后,利用高斯求和公式进行巧算是难点.
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