优优班--学霸训练营 > 知识点挑题
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            • 1.

              已知在数列\(\{a_{n}\}\)中,\(a_{1}=3\),\(a_{2}=6\),且\(a_{n+2}=a_{n+1}-a_{n}\),则\(a_{2015}\)等于\((\)  \()\)


              A.\(3\)                                             
              B.\(-3\)

              C.\(6\)                                              
              D.\(-6\)
            • 2.

              已知数列\(\{a_{n}\}\)满足\(a_{1}=2\),\(a_{n}=- \dfrac{1}{a_{n-1}+1}(n\geqslant 2\)且\(n∈N^{*})\),若数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),则\(S_{2\;018}=\)________.

            • 3.

              已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),\(a_{1}=2\),\(S_{n}=a_{n}\left( \dfrac{n}{3}{+}r \right)(r∈R,n∈N^{*}).\)

              \((1)\) 求\(r\)的值及数列\(\{a_{n}\}\)的通项公式.

              \((2)\) 设\(b_{n}=\dfrac{n}{a_{n}}(n∈N^{*})\),记\(\{b_{n}\}\)的前\(n\)项和为\(T_{n}\).

              \(①\)当\(n∈N^{*}\)时,\(λ < T_{2n}-T_{n}\)恒成立,求实数\(λ\)的取值范围\(;\)

              \(②\)求证:存在关于\(n\)的整式\(g(n)\),使得\(\underset{n\mathrm{{-}}1}{\overset{i{=}1}{\mathrm{{∑}}}}(T_{i}+1)=T_{n}·g(n)-1\)对一切\(n\geqslant 2\),\(n∈N^{*}\)都成立.

            • 4.

              已知数列\(\{a_{n}\}\)满足\(a_{n+1}=a_{n}-a_{n-1}(n\geqslant 2)\),\(a_{1}=m\),\(a_{2}=n\),\(S_{n}\)为数列\(\{a_{n})\)的前\(n\)项和,则\(S_{2017}\)的值为\((\)    \()\)

              A.\(2017n-m\)
              B.\(n-2017m\)
              C.\(m\)
              D.\(n\)
            • 5.

              \((1)\)计算定积分\(∫_{−1}^{2} \sqrt{4−{x}^{2}}dx= \)________.

              \((2)\)设变量\(x\),\(y\)满足不等式组\(\begin{cases} & x+y-4\leqslant 0 \\ & x-3y+3\leqslant 0 \\ & x\geqslant 1 \end{cases}\),则\(z=\dfrac{|x-y-4|}{\sqrt{2}}\)的取值范围是________.

              \((3)\)已知椭圆\(\dfrac{{{x}^{2}}}{{{a}^{2}}}+\dfrac{{{y}^{2}}}{{{b}^{2}}}=1(a > b > 0)\)的左、右焦点分别为\(F_{1}(-c,0)\),\(F_{2}(c,0)\),若椭圆上存在点\(P\)使\(\dfrac{a}{\sin \angle P{{F}_{1}}{{F}_{2}}}=\dfrac{c}{\sin \angle P{{F}_{2}}{{F}_{1}}}\)成立,则该椭圆的离心率的取值范围为________.

              \((4)\)用\(g(n)\)表示自然数\(n\)的所有因数中最大的那个奇数,例如:\(9\)的因数有\(1\),\(3\),\(9\),\(g(9)=9\),\(10\)的因数有\(1\),\(2\),\(5\),\(10\),\(g(10)=5\),那么\(g(1)+g(2)+g(3)+…+g(2^{2015}-1)=\)________.

            • 6.

              设数列\(\{a_{n}\}\)是集合\(\{3^{s}+3^{t}|0\leqslant s < t\),且\(S\),\(t∈Z\}\)中所有的数从小到大排列成的数列,即\(a_{1}=4\),\(a_{2}=10\),\(a_{3}=12\),\(a_{4}=28\),\(a_{5}=30\),\(a_{6}=36\),\(…\),将数列\(\{a_{n}\}\)中各项按照上小下大,左小右大的原则排成如图等腰直角三角形数表,\(a_{200}\)的值为\((\)    \()\)

              A.\(3^{9}+3^{19}\)
              B.\(3^{10}+3^{19}\)
              C.\(3^{19}+3^{20}\)
              D.\(3^{10}+3^{20}\)
            • 7. 在各项均为正数的等比数列\(\{a_{n}\}\)中,\(a_{1}=2\),且\(2a_{1}\),\(a_{3}\),\(3a_{2}\)成等差数列.
              \((\)Ⅰ\()\) 求等比数列\(\{a_{n}\}\)的通项公式;
              \((\)Ⅱ\()\) 若数列\(\{b_{n}\}\)满足\(b_{n}=11-2\log _{2}a_{n}\),求数列\(\{b_{n}\}\)的前\(n\)项和\(T_{n}\)的最大值.
            • 8.

              数列\(\left\{ {{a}_{n}} \right\}\)中,\({{S}_{n}}\)是\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和且\({{S}_{n}}=2n-{{a}_{n}}\),

              \((1)\)求\({a}_{1},{a}_{n} \)

              \((2)\)若数列\(\left[{b}_{n}\right] \)中,\({b}_{n=}n(2-n)({a}_{n}-2) \),且对任意正整数\(n\),都有\({b}_{n}+t\leqslant 2{t}^{2} \),求\(t \)的取值范围.

            • 9.

              等比数列\(\{a_{n}\) \(\}\)的前\(n\)项和为\({{S}_{n}}\), 已知对任意的\(n\in {{N}^{+}}\)  ,点\((n,{{S}_{n}})\),均在函数\(y={{b}^{x}}+r(b > 0\)且\(b\ne 1,b,r\)均为常数\()\)的图像上.

              \((1)\)求\(r\)的值;     

              \((11)\)当\(b=2\)时,记 \({{b}_{n}}=2({{\log }_{2}}{{a}_{n}}+1)(n\in {{N}^{+}})\)   证明:对任意的\(n\in {{N}^{+}}\) ,不等式\(\dfrac{{{b}_{1}}+1}{{{b}_{1}}}{ }\!\!\cdot\!\!{ }\dfrac{{{b}_{2}}+1}{{{b}_{2}}}{ }\!\!\cdot\!\!{ }\!\!\cdot\!\!{ }\!\!\cdot\!\!{ }\!\!\cdot\!\!{ }\!\!\cdot\!\!{ }\!\!\cdot\!\!{ }\dfrac{{{b}_{n}}+1}{{{b}_{n}}} > \sqrt{n+1}\)成立

            • 10.
              设数列\(\{a_{n}\}\)是公比小于\(1\)的正项等比数列,\(S_{n}\)为数列\(\{a_{n}\}\)的前\(n\)项和,已知\(S_{2}=12\),且\(a_{1}\),\(a_{2}+1\),\(a_{3}\)成等差数列.
              \((1)\)求数列\(\{a_{n}\}\)的通项公式;
              \((2)\)若\(b_{n}=a_{n}⋅(n-λ)\),且数列\(\{b_{n}\}\)是单调递减数列,求实数\(λ\)的取值范围.
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