不等式求证已知a1a2a3...an=1 求证a1a2+a2a3+...+a(n-1)an+ana1
已知数列{an},若1/a1a2+1/a2a3+…+1/anan-1=n/anan+1,求证{an}为等差数列.
【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
{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)=(
已知数列{an}的前n项和Sn=n²+n,求和1/a1a2+1/a2a3+.+1/an-1*an+1/an*a
已知数列an满足a1=1,a(n+1)=an/{3(an)+1} Sn=a1a2+a2a3+.+an(an+1),求Sn
已知{an}是等比数列,a2=2,a5=1/4,a1a2+a2a3+.+ana(n+1)
(a1+a2+a3+.+an)^2=a1^2+a2^2+.+an^2+2(a1a2+a2a3+...+a(n-1)an)
已知{an} a1=-3.4Sn=(2n+3)an+1 (1)求an(2)求和1/a1a2+1/a2a3+```+1/a
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的前n项和是Sn=n^2,则1/a1a2+1/a2a3+...+1/a(n-1)an=?
数列a1=1,an=an+1(1+2an)求证数列an分之一等差数列,若a1a2+a2a3+..+anan+1大于33分
已知n个正数满足a1a2...an=1,求证(2+a1)(2+a2)...(2+an)≥3^n