等差数列{an}中,Sn是其前n项和, a1=−11, S10 10− S8 8=2,则S11=( )A.-11B.11C.10D.-10 扫码下载作业帮搜索答疑一搜即得 答案解析 查看更多优质解析 解答一 举报 Sn=na1+ n(n−1) 2d,得 Sn n=a1+ (n−1) 2d,由 S10 10− S8 8=2,得 a1+ 10−1 2d−(a1+ 8−1 ...
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发明人: I Werner 摘要: A freezer chest (1), with a temporary cover in the form of a multi layered foil (3), comprises an interior which is divided into three zones (2, 5, 4) respectively occupied by frozen goods, a layer of flowing cold air and a layer of stationary air.收藏...