问题 解答题
探究并计算(大胆实践,你一定能探索成功!)
观察后面等式:
1
1×2
=1-
1
2
1
2×3
=
1
2
-
1
3
1
3×4
=
1
3
-
1
4
,将前面三个等式两边分别相加得:
1
1×2
+
1
2×3
+
1
4=1-
1
2
+
1
2
-
1
3
+
1
3
-
1
4
=1-
1
4
=
3
4

(1)猜想并写出:
1
n(n+1)
=______.
(2)直接写出下面式子的计算结果:
1
1×2
+
1
2×3
+
1
3×4
+…+
1
2006×2007
=______.
(3)探究并计算:
1
2×4
+
1
4×6
+
1
6×8
+…
1
2006×2008
答案

(1)

1
n(n+1)
=
1
n
-
1
n+1

(2)

1
1×2
+
1
2×3
+
1
3×4
+…+
1
2006×2007

=1-

1
2
+
1
2
-
1
3
+…+
1
2006
-
1
2007

=1-

1
2007

=

2006
2007

(3)

1
2×4
+
1
4×6
+
1
6×8
+…
1
2006×2008

=(

1
2
-
1
4
1
2
+(
1
4
-
1
6
1
2
+(
1
6
-
1
8
1
2
+…+(
1
2006
-
1
2008
1
2

=(

1
2
-
1
4
+
1
4
-
1
6
+
1
6
-
1
8
+…+
1
2006
-
1
2008
1
2

=(

1
2
-
1
2008
1
2

=

1003
2008
×
1
2

=

1003
4016

故答案为:

1
n
-
1
n+1
2006
2007
1003
4016

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