若数列{an }是等差数列
若数列{an},{bn}都是等差数列,s,t 为已知常数,求证数列{ s an+t bn}是等差数列
已知数列an是等差数列,首项a1
数列 An+1/1 是等差数列 求数列 An 是等差数列
若数列{an},{bn}是等差数列,公差分别为d1,d2,则数列{a2n},{an,2bn)是不是等差数列?如果是,公差
已知数列{an}是等差数列,且bn=3an+1 1.求证:数列{bn}是等差数列 2.若a1=2,
若数列An是等差数列,则有数列Bn=a1+a2+a3+a4+...+an/n也是等差数列,类比上述性质,相应的,若数列C
已知数列{lgAn}是等差数列,求证{An}是等比数列
已知数列an是等差数列,bn是等比数列
已知数列{an}是等差数列,数列{bn}是等比数列,a1=b1=1,若cn=an+bn,且c2=6,c3=11,求数列{
数列{an}是公差d≠0的等差数列,数列{bn}是等比数列,若a1=b1
已知数列{an}是等差数列,且bn=an+a(n-1),求证bn也是等差数列
设数列an,bn满足:bn=(a1+a2+a3+a4+...+an)/n,若bn是等差数列,求证an也是等差数列