数列是等差数列,证明Sn = An^2 + Bn
已知数列an满足a1=2 其前n项和为Sn Sn =n+7~3an 数列bn满足 bn=an~1 证明数列bn是等差数列
a1=1.an+1=2an+2^n.bn=an/2^n-1.证明bn是等差数列、求数列的前n项和sn?
数列(an)的前n项和Sn=an的2次方+bn,试证明数列是等差数列,并求a1和d
已知数列{an}的前n项和sn满足sn=an^2+bn,求证{an}是等差数列
试证明:数列{an}为等差数列的充要条件是其前n项和Sn=an^2+bn(常数a,b∈R) 感激.
已知数列{an}是等差数列,公差d>0,前n项和Sn=【(an+1)/2】^2,bn=(-1)^n*Sn,求数列{bn}
证明:数列{an}为等差数列的充要条件是数列{an}的前n项和为sn=an²+bn(其中啊a,b为常数)
数列{an}.a1=4,an=4-4/an-1(n>1),bn=1/(an-2),证明数列{bn}是等差数列,及求出数列
数列an的前n项和为Sn,Sn=4an-3,①证明an是等比数列②数列bn满足b1=2,bn+1=an+bn.求数列bn
1.已知数列{an}是等差数列,a1=2,a1+a2+a3=12,令bn=3^an,求数列{bn}的前n项和Sn.
已知等比数列{bn}是公比为q与数列{an}满足bn=3^an,(1)证明数列{an}是等差数列 (2)若b8=3,且数
数列{an}的前n项和sn=an2 +bn(a,b为常数),试证明{an}是等差数列,并求a1和d.