等差数列a1=1,d=2,求1 /a1a2+1/a2a3+1/a3a4+…1/a2007a2008
等差数列a1=1,d=2,求1 /a1a2+1/a2a3+1/a3a4+…1/a2007a2008
等差数列{1\an}满足a1=1,公差d=2,求a1a2+a2a3+……+anan+1的和
若a1,a2,..an是非零实数,且成等差数列,求证1/a1a2+1/a2a3+1/a3a4+...+1/an-1an=
已知an+1=1/1+1/an(n=1,2,3,...2007),求当a1=1时,a1a2+a2a3+a3a4+...+
已知an=2n(n∈N*),则a1a2+a2a3+a3a4+……+anan+1=
已知数列an为首项a1≠0,公差为d≠0的等差数列,求Sn=1/a1a2+1/a2a3+……+1/ana(n+1)
已知数列an为首项a1≠0,公差为d≠0的等差数列,求Sn=1/a1a2+1/a2a3+……+1/ana(n-1)
(1)等差数列{1/an}满足a1=1,公差d=2,求a1a2+a2a3+...+ana(a+1)的和
设{an}是等差数列,且首项a1>0,公差d>0求证:1/a1a2+1/a2a3+…+1/anan+1=n/a1(a1+
已知数列{an}是等比数列,a2=2,a5=6,则a1a2+a2a3+a3a4+...+ana(n+1)=
已知{an}是等比数列,a2=2,a4=8,则a1a2+a2a3+a3a4+...+ana(n+1)=?
已知数列an的首项a1不等于0,公差d不等于0,的等差数列,求Sn=1./a1a2+1/a2a3+.+1/ana(n+1