己知an是等差数列 a2+a4=6 a5=5 {bn}满足bn=anan+1则1/b1+1/b2+……+1/bn等于
己知an是等差数列 a2+a4=6 a5=5 {bn}满足bn=anan+1则1/b1+1/b2+……+1/bn等于
己知an是等差数列 a2+a4=6 a5=5 {bn}满足bn=an(an+1)则1/b1+1/b2+……+1/bn等于
设数列{An}{Bn} 满足A1=B1= A2=B2=6 A3=B3=5且{An+1-An}是等差数列{Bn+1-Bn}
已知等差数列{an}满足a2=3,a5=9,若数列{bn}满足b1=3, bn+1=abn,则{bn}的通项公
等差数列{an}中an=2n+1,等比数列{bn}满足b1=a2,b2=a4求{bn}前n项和Sn
已知等差数列{an}中,a2+a4=10 a5=9,数列{bn}中,b1=a1,bn+1=bn+an
设数列{an}、{bn}满足:a1=b1=6,a2=b2=4,a3=b3=3,且数列{an+1-an}是等差数列,{bn
设数列{an}是一等差数列,数列{bn}的前n项和为Sn=23(bn−1),若a2=b1,a5=b2.
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
有两个等差数列{an},{bn},满足a1+a2+…+an/(b1+b2+…+bn)=5n/(3n+6),则a7/b7=
an为等差数列,bn为等比数列,a1=b1=1,a2+a4=b3,b2*b4=a3,求an的前10项和及bn
在等差数列{an},等比数列{bn}中,a1=b1=1,a2=b2,a4=b3不等于b4.