摘要:五.请你解答下列各题
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阅读下列材料:1×2=
×(1×2×3-0×1×2),2×3=
×(2×3×4-1×2×3),3×4=
×(3×4×5-2×3×4),由以上三个等式相加,可得1×2+2×3+3×4=
×3×4×5=20.读完以上材料,请你计算下列各题:
(1)1×2+2×3+3×4+…+10×11(写出过程);
(2)1×2+2×3+3×4+…+n×(n+1)=
n(n+1)(n+2)
n(n+1)(n+2);
(3)1×2×3+2×3×4+3×4×5+…+7×8×9=
查看习题详情和答案>>
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
(1)1×2+2×3+3×4+…+10×11(写出过程);
(2)1×2+2×3+3×4+…+n×(n+1)=
| 1 |
| 3 |
| 1 |
| 3 |
(3)1×2×3+2×3×4+3×4×5+…+7×8×9=
1260
1260
.阅读下列材料:
=
=
-1,
=
=
-
,
=
=2-
,
=
=
-2.读完以上材料,请你计算下列各题:
(1)
=
-3
-3;
(2)
=
-
-
;
(3)
+
+
+…+
=
-1
-1.
查看习题详情和答案>>
| 1 | ||
1+
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(1+
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| 2 |
| 1 | ||||
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(
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| 3 |
| 2 |
| 1 | ||
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2-
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(
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| 3 |
| 1 | ||
2+
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(2+
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| 5 |
(1)
| 1 | ||
3+
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| 10 |
| 10 |
(2)
| 1 | ||||
|
| n+1 |
| n |
| n+1 |
| n |
(3)
| 1 | ||
1+
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| 1 | ||||
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| 1 | ||
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| 1 | ||||
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| 2011 |
| 2011 |
阅读下列材料:
12=
×1×2×3=1;
12+22=
×2×3×5=5;
12+22+32=
×3×4×7=14;
12+22+32+42=
×4×5×9=30;
…
读完以上材料,请你计算下列各题:
(1)12+22+32+42+…+102(写出过程)
(2)12+22+32+42+…+n2=
n(n+1)(2n+1)
n(n+1)(2n+1).
(3)22+42+62+82+…+1002=
查看习题详情和答案>>
12=
| 1 |
| 6 |
12+22=
| 1 |
| 6 |
12+22+32=
| 1 |
| 6 |
12+22+32+42=
| 1 |
| 6 |
…
读完以上材料,请你计算下列各题:
(1)12+22+32+42+…+102(写出过程)
(2)12+22+32+42+…+n2=
| 1 |
| 6 |
| 1 |
| 6 |
(3)22+42+62+82+…+1002=
17170
17170
.