数列{an}满足an+1=3an+n,问是否在适当的a1,使是等差数列

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数列{an}满足an+1=3an+n,问是否在适当的a1,使是等差数列
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数列{an}满足an+1=3an+n,问是否在适当的a1,使是等差数列
数列{an}满足an+1=3an+n,问是否在适当的a1,使是等差数列

数列{an}满足an+1=3an+n,问是否在适当的a1,使是等差数列
a(n+1)=3an+n
a(n+1) +(1/2)(n+1)+1/4= 3(an + (1/2)n + 1/4)
=>{an + (1/2)n + 1/4} 是等比数列,q=3
an + (1/2)n + 1/4 = 3^(n-1) .( a1 + 3/4)
等差数列
=> a1 + 3/4 =0
a1=- 3/4

a1 是确定的,数列是等差的

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