a1=2,(n+1)a(n+1)(角标)=nan,求an

问题描述:

a1=2,(n+1)a(n+1)(角标)=nan,求an

2a2=a1
3a3=2a2
4a4=3a3
.
nan=(n-1)an-1
等号两边相加,抵消,得到nan=a1,所以an=2/n