前n项和Sn=8n^2-3n,则 a10=?
问题描述:
前n项和Sn=8n^2-3n,则 a10=?
答
a10
=S10-S9
=770-621
=149
前n项和Sn=8n^2-3n,则 a10=?
a10
=S10-S9
=770-621
=149