已知数列{an}的前n项和为Sn,且a1=1,Sn=,则a2017=( )A.2016 B...
问题详情:已知数列{an}的前n项和为Sn,且a1=1,Sn=,则a2017=()A.2016 B.2017 C.4032 D.4034【回答】B∵a1=1,Sn=,∴当n≥2时,an=Sn-Sn-1=,可化为,∴=…==1,∴an=n....
问题详情:已知数列{an}的前n项和为Sn,且a1=1,Sn=,则a2017=()A.2016 B.2017 C.4032 D.4034【回答】B∵a1=1,Sn=,∴当n≥2时,an=Sn-Sn-1=,可化为,∴=…==1,∴an=n....