正项等差数列an,a5=8,a4*a6=60,求an和sn,设数列bn满足bn=1/sn,求Tn
正项等差数列an,a5=8,a4*a6=60,求an和sn,设数列bn满足bn=1/sn,求Tn
an等差数列 bn前n项和sn满足sn=3(bn-1)/2 且a2=b1 a5=b2 ⑴求an bn通项 ⑵设tn为数列
在等差数列中,a2+a3+a4=15,a5=9,设bn=(根号三)1+an,求数列bn的前n项和sn
已知数列(an)是等差数列a2=3,a4+a5+a6=27,Sn为(an)前n项和.若bn=2/(an+1^an)求数列
已知数列{an}是等比数列,其中a3=1,且a4,a5+1,a6成等差数列,数列{an/bn}的前n项和Sn=(n-1)
数列an,满足Sn=n^2+2n+1,设bn=an*2^n,求bn的前n项和Tn
设数列{bn}的前n项和为sn,且bn=2-2sn;数列{an}为等差数列,且a5=14,a7=20求
设等差数列{an}的前n项和为Sn,a3 a4=8,S7=5a5(1)求an通项公式(2)若bn=
设数列Bn的前n项和为Sn,且Bn=2-2Sn.数列An为等差数列,且A5=10,A7=14.(1)求数列An、{bn}
数列an的前n项和为Sn,Sn=2an-1,数列bn满足b1=2,bn+1=an+bn.求数列bn的前n项和Tn
已知等差数列an中,a1+a3+a5=21,a2+a4+a6=27,Sn=4Sn=3bn-a1 求an,bn
设{an}是等差数列,{bn}是等比数列,Sn、Tn分别是数列{an}、{bn}的前n项和.若a3=b3,a4=b4,且