数列{an}满足a1=1,且对任意的正整数m,n都有am+n=am+an+mn,...

2025-06-26 13:04:16
推荐回答(1个)
回答1:

解答:解:令m=1,得an+1=a1+an+n=1+an+n,
∴an+1-an=n+1,
用叠加法:
an=a1+(a2-a1)+…+(an-an-1)
=1+2+…+n=
n(n+1)
2


1
an
=
2
n(n+1)
=2(
1
n
-
1
n+1
),

1
a1
+
1
a2
+…+
1
a2013
+
1
a2014
=2(1-
1
2
+
1
2
-
1
3
+…+
1
2014
-
1
2015
)
=2(1-
1
2015
)
=
4028
2015
.
故答案为:
4028
2015
.