关于a2a4a8的百科

• 已知等差数列{an}的公差和首项都不为零,且a2,a4,a8成等比数列,则=(　　)A.           ...

• 问题详情：已知等差数列{an}的公差和首项都不为零,且a2,a4,a8成等比数列,则=()A.              B.           C.           D.2【回答】 B解析设等差数列的首项为a1,公差为d,则a2=a1+d,a4=a1+3d,a8=a1+7d,因为a2,a4,a8成等比数列,故=...
• 2020-04-0520260

• 已知等差数列{an}的公差和首项都不等于0,且a2,a4,a8成等比数列,则=(　　)A.2         ...

• 问题详情：已知等差数列{an}的公差和首项都不等于0,且a2,a4,a8成等比数列,则=()A.2              B.3           C.5              D.7【回答】B由题意,得=a2a8,∴(a1+3d)2=(a1+d)(a1+7d),∴d2=a1d,∵d≠0,∴d=a1,∴=3.知识点：数列...
• 2021-10-2617884