正项比例数列{an}与等差数列{bn}满足a1=b1,a7=b7,比较b4与a4的大小
设数列an,bn都是等差数列若a1+b1=5 a7+b7=15则a4+b4=
已知等差数列{an}和正项等比数列{bn},a1=b1=1,a3+a5+a7=9,a7是b3、b7的等比中项...
设{an}为等差数列,{bn}为等比数列又a1=b1,a3=b3,a7=b5.比较的a15和b7大小关系,给出证明
已知{an}是等差数列 满足a1=3 a4=12 数列{bn}满足b1=4 b4=20 且{bn-an}为等比数列.
一道数列题目数列{an}的前n项和为Sn,且an是Sn和1的等差中项,等差数列{bn}满足b1=a1,b4=a4 求数列
已知等差数列{an}和正项等比数列{bn},a1=b1=1,a3+a7=10,b3=a4
已知数列{an}的前n项和Sn满足Sn=2an-1,等差数列{bn}满足b1=a1,b4=S3.
有两个等差数列{an},{bn},满足a1+a2+…+an/(b1+b2+…+bn)=5n/(3n+6),则a7/b7=
设等差数列{an}的公差与等比数列{bn}的公比都是d,d≠1,a1=b1,a4=b4,a10=b10
设正项数列{an}是公差不为零的等差数列,正项数列{bn}是等比数列,且a1=b1,a3=b3,a7=b5
设{an},{bn}分别为等差数列与等比数列,且a1=b1=4,a4=b4=1,则以下结论正确的是( )
两个等差数列{an},{bn},a1+a2+...+an/b1+b2+...+bn=7n+2/n+3,求a7/b7?急,