已知数列an的前n项和为sn=5/6n(n+3),1:求证an为等差数列 2:设bn=a3n+a
已知数列an的前n项和为sn=5/6n(n+3),1:求证an为等差数列 2:设bn=a3n+a
设数列an的前n项和为Sn,a1=1,an=(Sn/n)+2(n-1)(n∈N*) 求证:数列an为等差数列,
已知数列{an}的前n项和为Sn,a1=1,a(n+1)=1+2Sn.设bn=n/an,求证:数列{bn}的前n项和Tn
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}的前n项和Sn=-an-(1/2)^(n-1)+2(n为正整数).令bn=2^n*an,求证数列{bn}
已知数列{an}的前N项和为Sn 且an+1=Sn-n+3,a1=2,设Bn=n/Sn-n+2前N项和为Tn 求证Tn
设等差数列{an}的前 n项和为Sn,且 Sn=(an+1)^/2(n属于N*)若bn=(-1)nSn,求数列{bn}的
已知数列an的前n项和Sn=n^2,设bn=an/3n,记数列bn的前n项和为Tn,求证Tn=1-(n+1)/3^n
设数列an中的前n项的和为Sn,并且a1=1,Sn+1=4an+2,设bn=an比2的n次方,求证数列bn为等差数列
设数列{an}的前n项和为Sn,已知a1=a,an+1=Sn+3^n,n∈N+.设bn=Sn+3n,求数列{bn}的通项
设数列{an}的前n项和为sn,已知a1=a,an+1=sn+3^n,n∈N* (1)设bn=sn-3^n,求数列{bn
设数列﹛an﹜的前n项和为Sn,已知a1=5,an+1=Sn+3的n次方(n∈N*).令bn=Sn-3的n次方,求证﹛b