数列{an}满足an+1-an=1/2(n∈N*),a1=1/2,Sn是数列{an}的前n项和,则S100=_.
问题描述:
数列{an}满足an+1-an=
(n∈N*),a1=1 2
,Sn是数列{an}的前n项和,则S100=______. 1 2
答
由an+1-an=
(n∈N*)知:数列{an}为以1 2
为公差的等差数列,1 2
又a1=
,1 2
所以S100=100×
+1 2
×100×99 2
=2525,1 2
故答案为:2525.