若数列{an}前n项和sn=an-a,a∈R则{an}( ) A.必为等差数列 B.必为等比数列 C.是等差或等比或非等差非等比数列 D是等差或等比数列
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![若数列{an}前n项和sn=an-a,a∈R则{an}( ) A.必为等差数列 B.必为等比数列 C.是等差或等比或非等差非等比数列 D是等差或等比数列](/uploads/image/z/15208911-63-1.jpg?t=%E8%8B%A5%E6%95%B0%E5%88%97%7Ban%7D%E5%89%8Dn%E9%A1%B9%E5%92%8Csn%3Dan-a%2Ca%E2%88%88R%E5%88%99%7Ban%7D%EF%BC%88+%EF%BC%89+A.%E5%BF%85%E4%B8%BA%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97+B.%E5%BF%85%E4%B8%BA%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97+C.%E6%98%AF%E7%AD%89%E5%B7%AE%E6%88%96%E7%AD%89%E6%AF%94%E6%88%96%E9%9D%9E%E7%AD%89%E5%B7%AE%E9%9D%9E%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97+D%E6%98%AF%E7%AD%89%E5%B7%AE%E6%88%96%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97)
若数列{an}前n项和sn=an-a,a∈R则{an}( ) A.必为等差数列 B.必为等比数列 C.是等差或等比或非等差非等比数列 D是等差或等比数列
若数列{an}前n项和sn=an-a,a∈R则{an}( ) A.必为等差数列 B.必为等比数列 C.是等差或等比或非等差非等比数列 D是等差或等比数列
若数列{an}前n项和sn=an-a,a∈R则{an}( ) A.必为等差数列 B.必为等比数列 C.是等差或等比或非等差非等比数列 D是等差或等比数列
Sn=An-A;
Sn-1=An-1-A;
做差:Sn-Sn-1=An-An-1
An=An-An-1
An-1=0
所以应该是:A