已知{An}为等比数列,A1=1,A4=27,Sn为等差数列{Bn}的前n项和,B1=3,S5=35....
已知{An}为等比数列,A1=1,A4=27,Sn为等差数列{Bn}的前n项和,B1=3,S5=35....
已知{an}为等比数列,a1=1,a4=27.Sn为等差数列{bn}的前n项和,b1=3,S5=35.
{an}为等比数列,a1=1,a6=243,Sn为等差数列{bn}的前N项和,b1=3,S5=35.Tn=a1+b1+.
已知{an}为等比数列,a1=1,a5=256;Sn为等差数列{bn}的前n项和,b1=2,5S5=2S8.
设等差数列an的前n项和为Sn,等比数列bn的前n项和为Tn,已知数列bn的公比为q(q>0),a1=b1=1,S5=4
已知等差数列{an}前n项和为Sn,公差d≠0,且S3+S5=50,a1,a4,a13,成等比数列 设{bn/an}是首
已知{an}是等差数列,其前n项和为sn,{bn}是等比数列,且a1=b1=2,a4+b4=27,s4-b4=10
已知{An}是等差数列,其前n项和为Sn,{Bn}是等比数列,且A1+B1=2,A4+Bb4=27,S4-B4=10
已知an是为正数的等比数列,a1=1,a5=256,Sn为等差数列bn的前n项和,b1=2,5S5=2S8
设等比数列{an}的前n项和为Sn 等比数列{bn}的前n项和Tn 已知数列{bn}的公比q>0 a1=b1=1 S5=
设{an}是等差数列,{bn}是等比数列,记{an}{bn}的前n项和分别为Sn,Tn若a3=b3,a4=b4,且(S5
\已知等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=2,且b2S2=32,b3S3