优优班--学霸训练营 > 题目详情
  • 设数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),若对任意的正整数\(n\),总存在正整数\(m\),使得\(S_{n}=a_{m}\),则称\(\{a_{n}\}\)是“\(H\)数列”.
    \((1)\)若数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}=2^{n}(n∈N^{*})\),证明:\(\{a_{n}\}\)是“\(H\)数列”;
    \((2)\)设\(\{a_{n}\}\)是等差数列,其首项\(a_{1}=1\),公差\(d < 0\),若\(\{a_{n}\}\)是“\(H\)数列”,求\(d\)的值;
    \((3)\)证明:对任意的等差数列\(\{a_{n}\}\),总存在两个“\(H\)数列”\(\{b_{n}\}\)和\(\{c_{n}\}\),使得\(a_{n}=b_{n}+c_{n}(n∈N^{*})\)成立.
    【考点】等差数列的概念,等差数列与等比数列的综合应用
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    【解答】请登陆后查看
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