优优班--学霸训练营 > 知识点挑题
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            • 1.
              已知数列:\( \dfrac {1}{1}\),\( \dfrac {2}{1}\),\( \dfrac {1}{2}\),\( \dfrac {3}{1}\),\( \dfrac {2}{2}\),\( \dfrac {1}{3}\),\( \dfrac {4}{1}\),\( \dfrac {3}{2}\),\( \dfrac {2}{3}\),\( \dfrac {1}{4}\),\(…\),依它的前\(10\)项的规律,这个数列的第\(2018\)项\(a_{2018}\)等于\((\)  \()\)
              A.\( \dfrac {1}{31}\)
              B.\( \dfrac {1}{63}\)
              C.\(64\)
              D.\( \dfrac {63}{2}\)
            • 2.
              已知\(\{a_{n}\}\)是等差数列,若\(a_{2}+a_{8}=10\),则\(a_{3}+a_{5}+a_{7}=\) ______
            • 3.
              等差数列\(\{a_{n}\}\)中,\(a_{n} > 0\),\(a_{1}^{2}+a_{7}^{2}+2a_{1}a_{7}=4\),则它的前\(7\)项的和等于\((\)  \()\)
              A.\( \dfrac {5}{2}\)
              B.\(5\)
              C.\( \dfrac {7}{2}\)
              D.\(7\)
            • 4.
              等差数列\(\{a_{n}\}\)中,\(a_{5}=1\),\(a_{1}+a_{7}+a_{10}=a_{4}+a_{6}\),则\(S_{10}=(\)  \()\)
              A.\(- \dfrac {2}{3}\)
              B.\( \dfrac {8}{3}\)
              C.\(5\)
              D.\( \dfrac {25}{3}\)
            • 5.
              设等差数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}.\)若\(a_{1}=2\),\(S_{4}=20\),则\(a_{3}=\) ______ ;\(S_{n}=\) ______ .
            • 6.
              设\(\{a_{n}\}\),\(\{b_{n}\}(n∈N*)\)时公差均不为零的等差数列,下列数列中,不构成等差数列的是\((\)  \()\)
              A.\(\{a_{n}⋅b_{n}\}\)
              B.\(\{a_{n}+b_{n}\}\)
              C.\(\{a_{n}+b_{n+1}\}\)
              D.\(\{a_{n}-b_{n+1}\}\)
            • 7.
              已知公差不为\(0\)的等差数列\(\{a_{n}\}\)满足\(a_{1}\),\(a_{3}\),\(a_{4}\)成等比数列,\(S_{n}\)为数列\(\{a_{n}\}\)的前\(n\)项和,则\( \dfrac {S_{3}-S_{2}}{S_{5}-S_{3}}\)的值为\((\)  \()\)
              A.\(2\)
              B.\(3\)
              C.\(-2\)
              D.\(-3\)
            • 8.
              已知数列\( \sqrt {2}, \sqrt {5},2 \sqrt {2}, \sqrt {11}…\),则\(2 \sqrt {5}\)是这个数列的\((\)  \()\)
              A.第\(6\)项
              B.第\(7\)项
              C.第\(11\)项
              D.第\(19\)项
            • 9.
              “中国剩余定理”又称“孙子定理”\(.1852\)年英国来华传教伟烈亚利将\(《\)孙子算经\(》\)中“物不知数”问题的解法传至欧洲\(1874\)年,英国数学家马西森指出此法符合\(1801\)年由高斯得出的关于同余式解法的一般性定理,因而西方称之为“中国剩余定理”\(.\)“中国剩余定理”讲的是一个关于整除的问题,现有这样一个整除问题:将\(2\)至\(2017\)这\(2016\)个数中能被\(3\)除余\(1\)且被\(5\)除余\(1\)的数按由小到大的顺序排成一列,构成数列\(\{a_{n}\}\),则此数列的项数为 ______ .
            • 10. 已知数列{an}的前n项和Sn=2n2-3,求:
              (1)第二项a2
              (2)通项公式an
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