优优班--学霸训练营 > 知识点挑题
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            • 1.

              若数列\(\{a_{n}\}\)满足\(a_{n+1}=1- \dfrac{1}{a_{n}}\),且\(a_{1}=2\),则\(a_{2018}\)等于\((\)  \()\)

              A.\(-1\)             
              B.\(2\)            
              C.\( \sqrt{2}\)
              D.\( \dfrac{1}{2}\)
            • 2.
              已知数列\(-3\),\(7\),\(-11\),\(15…\),则下列选项能表示数列的一个通项公式的是\((\)  \()\)
              A.\(a_{n}=4n-7\)
              B.\(a_{n}=(-1)^{n}(4n+1)\)
              C.\(a_{n}=(-1)^{n}⋅(4n-1)\)
              D.\(a_{n}=(-1)^{n+1}⋅(4n-1)\)
            • 3.
              按数列的排列规律猜想数列\( \dfrac {2}{3}\),\(- \dfrac {4}{5}\),\( \dfrac {6}{7}\),\(- \dfrac {8}{9}\),\(…\)的第\(10\)项是\((\)  \()\)
              A.\(- \dfrac {16}{17}\)
              B.\(- \dfrac {18}{19}\)
              C.\(- \dfrac {20}{21}\)
              D.\(- \dfrac {22}{23}\)
            • 4.
              已知等差数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),等比数列\(\{b_{n}\}\)的各项均为正数,公比为\(q\),且满足:\(a_{1}=3\),\(b_{1}=1\),\(b_{2}+S_{2}=12\),\(S_{2}=b_{2}q.\)
              \((1)\)求\(a_{n}\)与\(b_{n}\);
              \((2)\)设\(c_{n}=3b_{n}-2λ⋅ \dfrac {a_{n}}{3}(λ∈R)\),若数列\(\{c_{n}\}\)是递增数列,求\(λ\)的取值范围.
            • 5.
              已知数列\(\{a\) \(\}\)满足\(a= \dfrac {4}{3}\),\(a_{n+1}-1=a_{n}^{2}-a_{n}\) \((n∈N^{*})\),则\(m= \dfrac {1}{a_{1}}+ \dfrac {1}{a_{2}}+…+ \dfrac {1}{a_{2017}}\)的整数部分是\((\)  \()\)
              A.\(1\)
              B.\(2\)
              C.\(3\)
              D.\(4\)
            • 6.

              在小时候,我们就用手指练习过数数,一个小朋友按如图所示的规则练习数数,则大拇指对应的第\(253\)个数是________.

            • 7.

              已知数列\(\{{{a}_{n}}\}\)满足\({{a}_{1}}=1,{{a}_{2}}=1,{{a}_{n+1}}=|{{a}_{n}}-{{a}_{n-1}}|(n\geqslant 2)\), 则该数列前\(2017\)项的和等于\((\) \()\)

              A.\(1342\)        
              B.\(1343\)           
              C.\(1344\)           
              D.\(1345\)
            • 8.

              已知数列的通项公式为\({a}_{n}=(-1{)}^{n} \dfrac{n}{n+1} \)\({a}_{3}= \)\((\)    \()\)

              A.\(- \dfrac{2}{3} \)
              B.\( \dfrac{3}{4} \)
              C..\(- \dfrac{3}{4} \)
              D.\( \dfrac{2}{3} \)
            • 9.

              设\( \dfrac{1}{3n-1}f(n)=1+ \dfrac{1}{2}+ \dfrac{1}{3}+…+ \dfrac{1}{3n-1} (\)\(n∈{N}^{*} \)\()\),那么\(f(n+1)-f(n) \)等于(    )

              A.\(\dfrac{1}{3n+2}\)
              B.\(\dfrac{1}{3n}+\dfrac{1}{3n+1}\)
              C.\( \dfrac{1}{3n+1}+ \dfrac{1}{3n+2} \)
              D.\( \dfrac{1}{3n}+ \dfrac{1}{3n+1}+ \dfrac{1}{3n+2} \)
            • 10. 数列\(1\),\(1\),\(2\),\(3\),\(x\),\(8\),\(13\),\(21\),\(…\)中的\(x\)值为 ______ .
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