设数列{an}的前n项和Sn=2an-2^n,1;求a3,a4
设数列{an}的前n项和Sn=2an-2^n,1;求a3,a4
设数列an的前n项和sn=2an-2^n 求a3 a4
设数列{An}的前n项和Sn=2a-2n平方.1求a3,a4
设数列An的前n项和Sn=2An-2^n 求A3,A4 证明A(n+1)-2An为等比
已知数列an的前n项和sn=2an-2^n求a3、a4
设数列{an}的前n项和为Sn,a1=1,Sn=nan-2n(n-1) (1)求a2,a3,a4,并求出数列{an}的通
设数列{an}的前n项和为Sn,且a1=1,Sn=nan-2n(n-1) (1)求a2,a3,a4,并求出数列{an}的
设数列{an}的前n项和为Sn,a1=1,且3a(n+1)=Sn,(1)求a2,a3,a4及an (2)求a2+a4+·
已知数列{an}的前n项和sn=n^2+2n+3,求和1/a1+a2+1/a2+a3+1/a3+a4+.+1/an+an
设数列An的前n项和Sn=2An-2n的次方,求A1,A4
设数列{an}的前n项和为Sn,并且满足2Sn=an²+n,an>0.(1)求a1,a2,a3.(2)猜想{a
数列an满足sn=3an-1/2 计算a1,a2,a3,a4 猜an通项 求an前n项和sn