若a1,a2,a3为等差数列,a2,a3,a4,成等比数列,1/a3,1/a4,1/a5,成等比数列,证明a1,a3,a5成等比数列若a1,a2,a3为等差数列,a2,a3,a4,成等比数列,1/a3,1/a4,1/a5,成等差数列,证明a1,a3,a5成等比数列

等差数列an,若a1+a2+a3.+a1000 B、a3+a98 设a1,a2,a3为正数,求证a1*a2/a3+a2*a3/a1+a3*a1/a2>=a1+a2+a3 已知数列a1,a2,a3为等差数列,数列a2,a3,a4为等比数列,且a1+a4=16,a2+a3=12,求a1,a2,a3,a4=? 已知数列a1,a2,a3为等比数列,数列a2,a3,a4为等差数列,且a1+a4=16,a2+a3=12,求a1,a2,a3,a4=? 若a1,a2,a3为等差数列,a2,a3,a4,成等比数列,1/a3,1/a4,1/a5,成等比数列,证明a1,a3,a5成等比数列若a1,a2,a3为等差数列,a2,a3,a4,成等比数列,1/a3,1/a4,1/a5,成等差数列,证明a1,a3,a5成等比数列 等差数列中若a1+a2+a3+a4+a5=20,a3=?a2+a4=? 若an成等差数列,且a1,a3,a7,成等比数列,则（a1+a3)/(a2+a4)为多少? 等差数列公差为2,a1,a2,a3成等比数列,则a1等于是a1,a3,a3成等比 等差数列a1+a2+a3=-15.a3+a4=-16 若a1,a2,a3,a4线性无关,则秩（a1+a2,a2+a3,a3+a4,a4+a1) 若a1,a2,a3,a4线性无关,则秩（a1+a2,a2+a3,a3+a4,a4+a1) a1、a2、a3、a4为列向量若|a1 a2 a3|=3,|a4 a2 a1|=2,则|a1+a4+a3 a1 a2|= 等差数列{an}中,若a1+a3+a5=-1,则a1+a2+a3+a4+a5=? 若1,a2,a3,4成等差数列,求a2-a3 等差数列{an},a1+a2+a3=12,a2= 已知a1,a2,a3既是等差数列又是等比数列,且三个数之和为9,求a1*a2*a3 1.已知等差数列｛an｝中,a1*a2*a3=8,a1+a2+a3=6,求an为多少222 等差数列 A1+A2+A3=6,A2+A3+A4=7,A3+A4+A5=