已知数列{an}中,an=7^n+2,求证:数列{lgan}是等差数列
已知数列{lgAn}是等差数列,求证{An}是等比数列
已知在数列an中,Sn=2n^2+3n,求证an是等差数列
已知数列{lgan}是首项为3,公差为2的等差数列,求证:{an}是等比数列.
已知数列an是等比数列,a1=2,a4=16 设数列bn=lgan 求证bn是等差数列并求其前n项和
已知数列{An}满足A1=1,An+1=2An+2^n.求证数列An/2是等差数列
已知数列{lgan﹜是等差数列,求证﹛an﹜是等比数列.
已知数列{An}前n项和为Sn,A1=10,A(n+1)=9Sn+10.1,求证{lgAn}是等差数列.
已知数列{an}的前n项和为Sn=n^2-3n,求证:数列{an}是等差数列
已知数列{an}中a1=-1且(n+1)an,(n+2)an+1(是下标)成等差数列,设bn=(n+1)an-n+2求证
已知数列{an}满足:lgan=3n+5,试用定义证明{an}是等比数列 lgan=3n+5
已知数列{an}满足a1=3 an*a(n-1)=2a(n-1)-1,求证数列{1/(an-1)}是等差数列,并求出数列
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