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  • 题型:解答题 题类:模拟题 难易度:中档

    已知数列\(\{a _{n} \}\)是首项为\(1\)的等差数列,数列\(\{b _{n} \}\)是公比不为\(1\)的等比数列,且满足\(a _{1} +a _{2} =b _{2}\),\(a _{2} +a _{3} =b _{3}\),\(a _{4} +a _{5} =b _{4}\).
    \((1)\)求数列\(\{a _{n} \}\),\(\{b _{n} \}\)的通项公式;
    \((2)\)令\(c_{n}= \dfrac {a_{n+2}b_{n+2}}{(a_{n}b_{n}+1)(a_{n+1}b_{n+1}+1)}(n∈N^{*})\),记数列\(\{c _{n} \}\)的前\(n\)项和为\(S _{n}\),求证:对任意的\(n∈N*\),都有\(1 < S_{n} < \dfrac {4}{3}\);
    \((3)\)若数列\(\{d _{n} \}\)满足\(d _{1} =1\),\(d _{n} +d _{n+1} =b _{n}\),记\(T_{n}= \sum\limits_{k=1}^{n} \dfrac {d_{k}}{b_{2k}}\),是否存在整数\(λ\),使得对任意的\(n∈N*\)都有\(1\leqslant λT_{n}- \dfrac {d_{n}}{b_{2n}} < 2\)成立?若存在,求出\(λ\)的值;若不存在,说明理由.
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