题目内容
细心观察,认真分析,然后解答问题:
(1)用含n(n是正整数)的等式表示上述变化规律______;
(2)OA10的长______;
(3)求出
+
+
+…+
的值.
|
(1)用含n(n是正整数)的等式表示上述变化规律______;
(2)OA10的长______;
(3)求出
S | 21 |
S | 22 |
S | 23 |
S | 210 |
(1)根据所给图形,可得OAn=(
)2+12=n,则Sn=
×1×
=
;
即可得规律:(
)2+12=n,Sn=
×1×
=
;
(2)由(1)得OAn=
,故OA10=
;
(3)S12+S22+S32+…+S102=(
)2+(
)2+(
)2+…+(
)2
=
+
+
+
+
+…+
=
.
故答案为:(
)2+12=n,Sn=
;
.
n-1 |
1 |
2 |
n |
| ||
2 |
即可得规律:(
n-1 |
1 |
2 |
n |
| ||
2 |
(2)由(1)得OAn=
n |
10 |
(3)S12+S22+S32+…+S102=(
1 |
2 |
| ||
2 |
| ||
2 |
| ||
2 |
=
1 |
4 |
2 |
4 |
3 |
4 |
4 |
4 |
5 |
4 |
10 |
4 |
=
55 |
4 |
故答案为:(
n-1 |
| ||
2 |
10 |
练习册系列答案
相关题目