等差数列{An},A1>0,d0,An+1题目改一下“又有Sn>0,Sn+1

来源:学生作业帮助网 编辑:作业帮 时间:2024/08/02 07:36:56
等差数列{An},A1>0,d0,An+1题目改一下“又有Sn>0,Sn+1
x){uϦnx11V@'@1Og{6e Ovt?jٜ<`"}FU6GΆ*0 6~c޼ w>lN%˟6+xԱ%.HD Mtl i:j S*u l @

等差数列{An},A1>0,d0,An+1题目改一下“又有Sn>0,Sn+1
等差数列{An},A1>0,d0,An+1
题目改一下“又有Sn>0,Sn+1

等差数列{An},A1>0,d0,An+1题目改一下“又有Sn>0,Sn+1
(1)S3为前n项和最大值,
∴S3>S2,S3>S4,
∴A3>0>A4,n=3.
(2)A1+2d>0>A1+3d,
∴-A1/2