题目
题型:不详难度:来源:
1 |
1×2 |
1 |
2 |
1 |
2×3 |
1 |
2 |
1 |
3 |
1 |
3×4 |
1 |
3 |
1 |
4 |
1 |
n(n+1) |
根据找到的规律计算:
(1)
1 |
1×2 |
1 |
2×3 |
1 |
n(n+1) |
1 |
1×3 |
1 |
3×5 |
1 |
5×7 |
1 |
7×9 |
1 |
9×11 |
答案
1 |
n(n+1) |
1 |
n |
1 |
n+1 |
∵
1 |
1×1 |
1 |
2×3 |
1 |
n(n+1) |
=1-
1 |
2 |
1 |
2 |
1 |
3 |
1 |
3 |
1 |
n |
1 |
n+1 |
=1-
1 |
n+1 |
n |
n+1 |
(2)
1 |
1×3 |
1 |
3×5 |
1 |
5×7 |
1 |
7×9 |
1 |
9×11 |
=
1 |
2 |
1 |
3 |
1 |
2 |
1 |
3 |
1 |
5 |
1 |
2 |
1 |
5 |
1 |
7 |
1 |
2 |
1 |
7 |
1 |
9 |
1 |
2 |
1 |
9 |
1 |
11 |
=
1 |
2 |
1 |
3 |
1 |
3 |
1 |
11 |
=
5 |
11 |
核心考点
试题【已知11×2=1-12;12×3=12-13;13×4=13-14;…你能总结出1n(n+1)等于什么吗?(其中n为正整数)根据找到的规律计算:(1)11×2+】;主要考察你对数据的整理与描述等知识点的理解。[详细]
举一反三
1 |
3 |
1 |
3 |
1 |
5 |
1 |
5 |
1 |
7 |
1 |
7 |
1 |
9 |
①
2+
|
|
3+
|
|
③
4+
|
|
5+
|
|
(2)你判断完以上各题之后,请猜测你发现的规律,用含n的式子将其规律表示出来,并注明n的取值范围:______.