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            • 1.

              已知\(-9\),\(a_{1}\),\(a_{2}\),\(-1\)成等差数列,\(-9\),\(b_{1}\),\(b_{2}\),\(b_{3}\),\(-1\)成等比数列 ,则\(b_{2}(a_{1}+a_{2})\)等于\((\)    \()\)

              A.\(30\)          
              B.\(-30\)           
              C.\(±30\)       
              D.\(15\)
            • 2.
              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.
            • 3.

              在数列\(\{a_{n}\}\),\(\{b_{n}\}\)中,已知\(a_{1}=0\),\(a_{2}=1\),\(b_{1}=1\),\(b_{2}=\dfrac{1}{2}\),数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),数列\(\{b_{n}\}\)的前\(n\)项和为\(T_{n}\),且满足\(S_{n}+S_{n+1}=n^{2}\),\(2T_{n+2}=3T_{n+1}-T_{n}\),其中\(n\)为正整数.

              \((1)\) 求数列\(\{a_{n}\}\),\(\{b_{n}\}\)的通项公式.

              \((2)\) 问:是否存在正整数\(m\),\(n\),使得\(\dfrac{T_{n{+}1}\mathrm{{-}}m}{T_{n}\mathrm{{-}}m} > 1+b_{m+2}\)成立\(?\)若存在,求出所有符合条件的有序实数对\((m,n);\)若不存在,请说明理由.

            • 4.

              我国古代数学著作\(《\)九章算术\(》\)中有如下问题:“今有蒲\((\)水生植物名\()\)生一日,长三尺\(;\)莞\((\)植物名,俗称水葱、席子草\()\)生一日,长一尺\(.\)蒲生日自半,莞生日自倍\(.\)问几何日而长等\(?\)”其大意是:今有蒲生长\(1\)日,长为\(3\)尺\(;\)莞生长\(1\)日,长为\(1\)尺\(.\)今后蒲的生长逐日减半,莞的生长逐日增加\(1\)倍\(.\)若蒲、莞长度相等,则所需的时间约为____日\(.(\)结果保留一位小数,参考数据:\(\lg 2≈0.30\),\(\lg 3≈0.48)\)

            • 5.

              设数列\(\left\{{a}_{n}\right\} \)的前\(n\)项和为\(S_{n}\),已知\({a}_{1}=2,{a}_{n+1}=2{S}_{n}+2\left(n∈{N}^{*}\right) \)

              \((1)\)求数列\(\left\{{a}_{n}\right\} \)通项公式;

              \((2)\)在\(a_{n}\)与\(a_{n+1}\)之间插入\(n\)个数,使这\(n+2\)个数组成一个公差为\(d_{n}\)的等差数列。

              \((\)Ⅰ\()\)求证:\(\dfrac{1}{{d}_{1}}+ \dfrac{1}{{d}_{2}}+ \dfrac{1}{{d}_{3}}+…+ \dfrac{1}{{d}_{n}} < \dfrac{15}{16}\left(n∈{N}^{*}\right) \)

              \((\)Ⅱ\()\)在数列\(\left\{{d}_{n}\right\} \)中是否存在三项\(d_{m}\),\(d_{k}\),\(d_{p}(\)其中\(m\),\(k\),\(p\)成等差数列\()\)成等比数列,若存在,求出这样的三项;若不存在,说明理由.

            • 6.

              已知数列\(\{an\}\)的首项\({a}_{1}= \dfrac{3}{5},{a}_{n+1}= \dfrac{3{a}_{n}}{2{a}_{n}+1},n∈{N}^{*} \).

              \((1)\)求证:数列\(\{ \dfrac{1}{{a}_{n}}-1\} \)为等比数列;

              \((2)\)记\({S}_{n}= \dfrac{1}{{a}_{1}}+ \dfrac{1}{{a}_{2}}+...+ \dfrac{1}{{a}_{n}} \),若\(S_{n} < 101\),求最大正整数\(n\)的值;

                  \((3)\)是否存在互不相等的正整数\(m\),\(s\),\(n\),使\(m\),\(s\),\(n\)成等差数列,且\(a_{m}-1\),\(a_{s}-1\),\(a_{n}-1\)成等比数列?如果存在,请给予证明;如果不存在,请说明理由.

            • 7.

              已知函数\(f(x)=4x+1\),\(g(x)=2x\),\(x∈R\),数列\(\{a_{n}\}\),\(\{b_{n}\}\),\(\{c_{n}\}\)满足条件:\(a_{1}=1\),\(a_{n}=f(b_{n})=g(b_{n+1})(n∈N^{*})\),\({{c}_{n}}=\dfrac{1}{[\dfrac{1}{2}f(n)+\dfrac{1}{2}][g(n)+3]}\).

              \((\)Ⅰ\()\)求数列\(\{a_{n}\}\)的通项公式;

              \((\)Ⅱ\()\)求数列\(\{c_{n}\}\)的前\(n\)项和\(T_{n}\),并求使得\({{T}_{n}} > \dfrac{m}{150}\)对任意\(n∈N^{*}\)都成立的最大正整数\(m\);

              \((\)Ⅲ\()\)求证:\(\dfrac{{{a}_{1}}}{{{a}_{2}}}+\dfrac{{{a}_{2}}}{{{a}_{3}}}+\cdots +\dfrac{{{a}_{n}}}{{{a}_{n+1}}} > \dfrac{n}{2}-\dfrac{1}{3}\).

            • 8.
              设\(\{a_{n}\}\)是各项都为正数的等比数列,\(\{b_{n}\}\)是等差数列,且\(a_{1}=b_{1}=1\),\(a_{3}+b_{5}=13\),\(a_{5}+b_{3}=21\).
              \((1)\)求数列\(\{a_{n}\}\),\(\{b_{n}\}\)的通项公式;
              \((2)\)求数\(\{a_{n}b_{n}\}\)列前\(n\)项和\(T_{n}\).
            • 9. 数列\(\{ \)\(a_{n}\)\(\}\)的前 \(n\)项和为 \(S_{n}\)\(a\)\({\,\!}_{1}=1\), \(S_{n}\)\({\,\!}_{+1}=4\) \(a_{n}\)\(+2( \)\(n\)\(∈N^{*})\),设 \(b_{n}\)\(=\) \(a_{n}\)\({\,\!}_{+1}-2\) \(a_{n}\)

              \((1)\)求证:\(\{\)\(b_{n}\)\(\}\)是等比数列;

              \((2)\)设\(c_{n}\)\(= \dfrac{a_{n}}{3n-1}\),求证:\(\{\)\(c_{n}\)\(\}\)是等比数列.

            • 10.

              已知\({数列}\{ a_{n}\}\)的前\(n\)项\({和}{为}A_{n}\),对\({任意}n{∈}N^{{*}}{满足}\dfrac{A_{n{+}1}}{n{+}1}{-}\dfrac{A_{n}}{n}{=}\dfrac{1}{2}{,}{且}a_{1}{=}1\),\({数列}\{ b_{n}\}{满}{足}b_{n{+}2}{-}2b_{n{+}1}{+}b_{n}{=}0(n{∈}N{*}){,}b_{3}{=}5\),其前\(9\)项和为\(63{.}(1)\)求\({数列}\{ a_{n}\}{和}\{ b_{n}\}\)的通项公式\({;}(2){令}c_{n}{=}\dfrac{b_{n}}{a_{n}}{+}\dfrac{a_{n}}{b_{n}}\),\({数列}\{ c_{n}\}\)的前\(n\)项\({和}{为}T_{n}\),若对任意正整数\(n\),\({都}{有}T_{n}{\geqslant }2n{+}a\),求实数\(a\)的取值范围\({;}(3)\)将\({数列}\{ a_{n}\}{,}\{ b_{n}\}\)的项按照“当\(n\)为奇数\({时}{,}a_{n}\)放在前面;当\(n\)为偶数\({时}{,}b_{n}\)放在前面”的要求进行“交叉排列”,得到一个新的数列:\({\ \ \ \ \ \ \ \ \ \ \ \ \ \ a}_{1}{,}b_{1}{,}b_{2}{,}a_{2}{,}a_{3}{,}b_{3}{,}b_{4}{,}a_{4}{,}a_{5}{,}b_{5}{,}b_{6}{,…}\),

              求这个新数列的前\(n{项}{和}S_{n}\).
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