∴(n+1)an+1=nan或an+1+an=0,
∵{an}是首項(xiàng)為1的正數(shù)項(xiàng)數(shù)列,
∴(n+1)an+1=nan,
∴an+1=
n |
n+1 |
即
an+1 |
an |
n |
n+1 |
∴
a2 |
a1 |
a3 |
a2 |
an |
an?1 |
an |
a1 |
1 |
2 |
2 |
3 |
n?1 |
n |
1 |
n |
故這個(gè)數(shù)列的通項(xiàng)公式為an=
1 |
n |
故答案為:an=
1 |
n |
n |
n+1 |
an+1 |
an |
n |
n+1 |
a2 |
a1 |
a3 |
a2 |
an |
an?1 |
an |
a1 |
1 |
2 |
2 |
3 |
n?1 |
n |
1 |
n |
1 |
n |
1 |
n |