an是首项为3,公差,公差为2的等差数列,则lim(1/a1a2+1/a2a3+……+1/a(n-1)an)=
an是首项为3,公差,公差为2的等差数列,则lim(1/a1a2+1/a2a3+……+1/a(n-1)an)=
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)
{an}为等差数列,an不等于0,d为公差,求证:1/(a1a2)+1/(a2a3)+...+1/(an-1*an)=(
等差数列{1\an}满足a1=1,公差d=2,求a1a2+a2a3+……+anan+1的和
已知等差数列公差为d,1/a1a2+1/a2a3+…+1/anan+1可化简为
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},若1/a1a2+1/a2a3+…+1/anan-1=n/anan+1,求证{an}为等差数列.
(1)等差数列{1/an}满足a1=1,公差d=2,求a1a2+a2a3+...+ana(a+1)的和
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
设(an)为公差大于0的等差数列,sn为其前n项和,s4=24,a2a3=35,(1)求(an)通项公式
【急】已知数列an满足1/a1a2+1/a2a3+……1/an-1an=(n-1)/a1an,求证为等差数列