问题 解答题
观察下列各式及其验证过程:2
2
3
=
2+
2
3
;,3
3
8
=
3+
3
8

验证:2
2
3
=
23
3
=
23-2+2
3
=
2(22-1)+2
3
=
2(22-1)+2
22-1
=
2+
2
22-1
=
2+
2
3
3
3
8
=
33
8
=
33-3+3
8
=
3(32-1)+3
8
=
3(32-1)+3
32-1
=
3+
3
32-1
=
3+
3
8

(1)按照上面结论猜想4
4
15
的结果,并写出验证过程;
(2)根据对上述各式规律,写出用n(n为正整数,且n≥2)表示的等式并给出证明.
答案

(1)4

4
15
=
4+
4
15

4

4
15

=

43
15

=

43-4+4
15

=

4(42-1)+4
15

=

4(42-1)+4
42

=

4+
4
42-1
=
4+
4
15

(2)n

n
n2-1

=

n+
n
n2-1
n+
n
n2-1

=

n2-n+n
n2-1

=

n3
n2-1

=n

n
n2-1

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