数列{an}的前n项和Sn=2n^2-1则a1等于
问题描述:
数列{an}的前n项和Sn=2n^2-1则a1等于
答
a1=S1
=2*1^2-1
=1
数列{an}的前n项和Sn=2n^2-1则a1等于
a1=S1
=2*1^2-1
=1