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  • 题型:解答题 题类:模拟题 难易度:较难

    已知公差非零的等差数列\(\{a _{n} \}\)的前\(n\)项和为\(S _{n} (n∈N*)\),且\(a _{1}\),\(a _{2}\),\(a _{4}\)成等比数列,且\(S _{4} =10\),数列\(\{b _{n} \}\)满足\(b _{1} =2\),\(b_{n}-b_{n-1}=2^{n-1}(n\geqslant 2,n∈N^{*})\).
    \((1)\)求数列\(\{a _{n} \}\)和\(\{b _{n} \}\)的通项公式;
    \((2)\)设数列\(\{c _{n} \}\)满足\(c_{n}= \dfrac {\ln a_{n}}{b_{n}},(n∈N^{+})\),求证:\((1- \dfrac {1}{2^{n-1}} )\boldsymbol{⋅}\ln \sqrt {2} \leqslant c _{2} +…+c _{n} < \dfrac {3}{4}\),\((n∈N ^{*} , n\geqslant 2)\).
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