设bn=1/2*3/4*5/6*...*(2n-1)/(2n) ,求证:b1+b2+...+bn
bn=2/(n^2+n) 求证b1+b2+.+bn
令bn=1/(n2+2n) Tn=b1+b2+b3+……+bn
设数列an,bn分别满足a1*a2*a3...*an=1*2*3*4...*n,b1+b2+b3+...bn=an^2,
已知数列bn,满足b1=1,b2=5,bn+1=5bn-6bn-1(n≥2),若数列an满足a1=1,an=bn(1/b
数列 an=2n-1 设bn=an/3^n 求和tn=b1+..bn?
AN=3^(n-1),b1/a1+b2/a2+...+bn/an=n(n+2),求{bn}的前n项和TN.要过程啊.
有两个等差数列an,bn,若Sn/Tn=a1+a2+.an/b1+b2+---+bn=3n-1/2n+3,则a13/b1
设A为n阶矩阵,r(A)=1,求证:(1)A=(a1 a2 .an)(列向量)*(b1,b2.bn ) (2) A^2=
等差数列an的前n项和胃Sn,bn=1/Sn,且a3b3=1/2,S3+S5=21.求证b1+b2+b3...+bn
数列{an}满足an=n(n+1)^2,是否存在等差数列{bn}使an=1*b1+2*b2+3*b3+...n*bn,对
放缩法证明题已知bn=2n,求证对于任意n∈N+,不等式(b1+1)(b2+1)···(bn+1)/b1b2···bn>
等差数列{an}中a2=8,S6=66.设bn=2/[(n+1)an],Tn=b1+b2+…+bn,