问题 填空题
1
1×5
+
1
5×9
+
1
9×13
+…+
1
33×37
=______.
7
12
=
1
()
+
1
()
=
1
()
+
1
()
答案

1
1×5
+
1
5×9
+
1
9×13
+…+
1
33×37

=

1
4
×(1-
1
5
+
1
5
-
1
9
+
1
9
-
1
13
+…+
1
33
-
1
37
),

=

1
4
×(1-
1
37
),

=

1
4
×
36
37

=

9
37

(2)

7
12
=
3+4
12
=
3
12
+
4
12
=
1
4
+
1
3

7
12
=
1+6
12
=
1
12
+
6
12
=
1
12
+
1
2

因此,

7
12
=
1
3
+
1
4
=
1
2
+
1
12

故答案为:

9
37
,3,4,2,12.

判断题
判断题