2025年高考模拟试题汇编高中数学


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《2025年高考模拟试题汇编高中数学》

11. 已知函数$f(x)=\cos x+\vert\sin\frac{x}{2}\vert$,则 ( )
A. $f(x)$在区间$(0,\frac{\pi}{6})$上单调递增
B. $f(x)$的图象关于直线$x = \pi$对称
C. $f(x)$的值域为$[0,\frac{9}{8}]$
D. 关于$x$的方程$f(x)=a$在区间$[0,2\pi]$上有实数根,则所有根之和组成的集合为$\{\pi,2\pi,4\pi\}$
答案:
ABD
12. 已知集合$A = \{ -1,0,1\}$,$B = \{ y\mid y = 2x,x\in A\}$,则$A\cup B$的所有元素之和为_______.
答案: 0
13. 已知$O$为坐标原点,$F$为椭圆$C:\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}=1$($a>b>0$)的右焦点,点$A$,$B$在$C$上,$AB$的中点为$F$,$OA\perp OB$,则$C$的离心率为_______.
答案: $\frac{\sqrt{6}}{3}$
14. 已知球$O$的表面积为$12\pi$,正四面体$ABCD$的顶点$B$,$C$,$D$均在球$O$的表面上,球心$O$为$\triangle BCD$的外心,棱$AB$与球面交于点$P$. 若$A\in$平面$\alpha_{1}$,$B\in$平面$\alpha_{2}$,$C\in$平面$\alpha_{3}$,$D\in$平面$\alpha_{4}$,$\alpha_{i}//\alpha_{i + 1}(i = 1,2,3)$且$\alpha_{i}$与$\alpha_{i + 1}(i = 1,2,3)$之间的距离为同一定值,棱$AC$,$AD$分别与$\alpha_{2}$交于点$Q$,$R$,则$\triangle PQR$的周长为_______.
答案:
$3\sqrt{3}$
15.(13分)
为促进全民阅读,建设书香校园,某校在寒假面向全体学生发出“读书好、读好书、好读书”的号召,并开展阅读活动. 开学后,学校统计了高一年级共1000名学生的假期日均阅读时间(单位:分钟),得到了如图所示的频率分布直方图,若前两个小矩形的高度分别为0.0075,0.0125,后三个小矩形的高度比为3∶2∶1.
(Ⅰ)根据频率分布直方图,估计高一年级1000名学生假期日均阅读时间的平均值(同一组中的数据用该组区间的中点值为代表);
(Ⅱ)开学后,学校从高一日均阅读时间不低于60分钟的学生中,按照分层随机抽样的方式,抽取6名学生作为代表分两周进行国旗下演讲,假设第一周演讲的3名学生日均阅读时间处于$[80,100)$的人数记为$\xi$,求随机变量$\xi$的分布列与数学期望.
20406080100120时间/分钟
答案: 平均数 + 离散型随机变量的分布列与数学期望 解:(Ⅰ)由题知,各组频率分别为\(0.15,0.25,0.3,0.2,0.1\) (题眼), 日均阅读时间的平均值为\(30\times0.15 + 50\times0.25+70\times0.3 + 90\times0.2+110\times0.1 = 67\). (Ⅱ)由题意,在\([60,80)\),\([80,100)\),\([100,120]\)三组分别抽取\(3,2,1\)人, \(\xi\)的可能取值为\(0,1,2\) (题眼), 则\(P(\xi = 0)=\frac{C_{3}^{0}C_{2}^{0}}{C_{6}^{2}}=\frac{1}{5}\), \(P(\xi = 1)=\frac{C_{3}^{1}C_{2}^{1}}{C_{6}^{2}}=\frac{3}{5}\), \(P(\xi = 2)=\frac{C_{3}^{2}C_{2}^{0}}{C_{6}^{2}}=\frac{1}{5}\), 则\(\xi\)的分布列为 | \(\xi\) | \(0\) | \(1\) | \(2\) | | ---- | ---- | ---- | ---- | | \(P\) | \(\frac{1}{5}\) | \(\frac{3}{5}\) | \(\frac{1}{5}\) | \(E(\xi)=0\times\frac{1}{5}+1\times\frac{3}{5}+2\times\frac{1}{5}=1\) (提示:数学期望计算公式). 
16.(15分)
已知函数$f(x)=\frac{1}{2}x^{2}-ax+\ln x$.
(Ⅰ)若$a = 1$,曲线$y = f(x)$在点$(x_{0},f(x_{0}))$处的切线斜率为1,求该切线的方程;
(Ⅱ)讨论$f(x)$的单调性.
答案:  导数的几何意义 + 利用导数研究函数的单调性 解:(Ⅰ)当\(a = 1\)时,\(f^{\prime}(x)=\frac{x^{2}-x + 1}{x}\), 则\(f^{\prime}(x_{0}) = 1\) (题眼), 解得\(x_{0}=1\). 因为\(f
(1)=-\frac{1}{2}\), 所以切线方程为\(x - y-\frac{3}{2}=0\). (Ⅱ)已知\(f(x)\)的定义域为\((0,+\infty)\),\(f^{\prime}(x)=\frac{x^{2}-ax + 1}{x}\) (题眼), 当\(a\leqslant0\)时,得\(f^{\prime}(x)\gt0\)恒成立,\(f(x)\)在\((0,+\infty)\)上单调递增; 当\(a\gt0\)时,令\(g(x)=x^{2}-ax + 1\),\(\Delta=a^{2}-4\), (ⅰ)当\(\Delta\leqslant0\),即\(0\lt a\leqslant2\)时, \(f^{\prime}(x)\geqslant0\)恒成立,\(f(x)\)在\((0,+\infty)\)上单调递增; (ⅱ)当\(\Delta\gt0\),即\(a\gt2\)时, \(f^{\prime}(x)=\frac{(x-\frac{a-\sqrt{a^{2}-4}}{2})(x-\frac{a+\sqrt{a^{2}-4}}{2})}{x}\), 由\(f^{\prime}(x)\gt0\),得\(0\lt x\lt\frac{a-\sqrt{a^{2}-4}}{2}\)或\(x\gt\frac{a+\sqrt{a^{2}-4}}{2}\), 由\(f^{\prime}(x)\lt0\),得\(\frac{a-\sqrt{a^{2}-4}}{2}\lt x\lt\frac{a+\sqrt{a^{2}-4}}{2}\), 所以\(f(x)\)在\((0,\frac{a-\sqrt{a^{2}-4}}{2})\),\((\frac{a+\sqrt{a^{2}-4}}{2},+\infty)\)上单调递增, 在\((\frac{a-\sqrt{a^{2}-4}}{2},\frac{a+\sqrt{a^{2}-4}}{2})\)上单调递减. 综上,当\(a\leqslant2\)时,\(f(x)\)在\((0,+\infty)\)上单调递增; 当\(a\gt2\)时,\(f(x)\)在\((0,\frac{a-\sqrt{a^{2}-4}}{2})\),\((\frac{a+\sqrt{a^{2}-4}}{2},+\infty)\)上单调递增,\(f(x)\)在\((\frac{a-\sqrt{a^{2}-4}}{2},\frac{a+\sqrt{a^{2}-4}}{2})\)上单调递减. 
17.(15分)
如图,在三棱柱$ABC - A_{1}B_{1}C_{1}$中,$AA_{1}$与$BB_{1}$的距离为$\sqrt{3}$,$AB = AC = A_{1}B = 2$,$A_{1}C = BC = 2\sqrt{2}$.
(Ⅰ)证明:平面$A_{1}ABB_{1}\perp$平面$ABC$;
(Ⅱ)若点$N$在棱$A_{1}C_{1}$上,求直线$AN$与平面$A_{1}B_{1}C$所成角的正弦值的最大值.
答案:
空间中线面间的位置关系 + 线面角的正弦值 + 空间向量的应用 解:(Ⅰ)证明:取棱$A_{1}A$的中点$D$,连接$BD$, 因为$AB = A_{1}B$,所以$BD\perp AA_{1}$. 因为三棱柱$ABC - A_{1}B_{1}C_{1}$, 所以$AA_{1}// BB_{1}$, 所以$BD\perp BB_{1}$,所以$BD=\sqrt{3}$. 因为$AB = 2$,所以$AD = 1$,所以$AA_{1}=2$. 因为$AC = 2$,$A_{1}C = 2\sqrt{2}$, 所以$AC^{2}+AA_{1}^{2}=A_{1}C^{2}$,所以$AC\perp AA_{1}$ (题眼), 同理$AC\perp AB$. 因为$AA_{1}\cap AB = A$,且$AA_{1},AB\subset$平面$A_{1}ABB_{1}$, 所以$AC\perp$平面$A_{1}ABB_{1}$ (提示:线面垂直的判定定理). 又因为$AC\subset$平面$ABC$, 所以平面$A_{1}ABB_{1}\perp$平面$ABC$ (提示:面面垂直的判定定理). (Ⅱ)取$AB$的中点$O$,连接$A_{1}O$, 取$BC$的中点$P$,连接$OP$,则$OP// AC$, 由(Ⅰ)知$AC\perp$平面$A_{1}ABB_{1}$, 所以$OP\perp$平面$A_{1}ABB_{1}$ (题眼). 因为$A_{1}O\subset$平面$A_{1}ABB_{1}$,$AB\subset$平面$A_{1}ABB_{1}$, 所以$OP\perp A_{1}O$,$OP\perp AB$. 因为$AB = A_{1}A = A_{1}B$,则$A_{1}O\perp AB$. 以$O$为坐标原点,$OP,OB,OA_{1}$所在的直线分别为$x$轴、$y$轴、$z$轴,建立如图所示的空间直角坐标系$O - xyz$, 则$A(0,-1,0)$,$A_{1}(0,0,\sqrt{3})$,$B_{1}(0,2,\sqrt{3})$,$C(2,-1,0)$, 设点$N(a,0,\sqrt{3})(0\leqslant a\leqslant2)$, 则$\overrightarrow{A_{1}B_{1}}=(0,2,0)$,$\overrightarrow{A_{1}C}=(2,-1,-\sqrt{3})$,$\overrightarrow{AN}=(a,1,\sqrt{3})$, 设平面$A_{1}B_{1}C$的法向量为$\boldsymbol{n}=(x,y,z)$, 则$\begin{cases}\boldsymbol{n}\cdot\overrightarrow{A_{1}B_{1}} = 0\\\boldsymbol{n}\cdot\overrightarrow{A_{1}C}=0\end{cases}$,即$\begin{cases}2y = 0\\2x - y-\sqrt{3}z = 0\end{cases}$, 取$x=\sqrt{3}$,则$y = 0$,$z = 2$, 则$\boldsymbol{n}=(\sqrt{3},0,2)$. 设直线$AN$与平面$A_{1}B_{1}C$所成角为$\theta$, 则$\sin\theta=\vert\cos\langle\boldsymbol{n},\overrightarrow{AN}\rangle\vert=\frac{\vert\boldsymbol{n}\cdot\overrightarrow{AN}\vert}{\vert\boldsymbol{n}\vert\cdot\vert\overrightarrow{AN}\vert}=\frac{\sqrt{3}(a + 2)}{\sqrt{7}\cdot\sqrt{a^{2}+4}}=\frac{\sqrt{3}}{\sqrt{7}}\cdot\sqrt{\frac{(a + 2)^{2}}{a^{2}+4}}=\frac{\sqrt{3}}{\sqrt{7}}\sqrt{\frac{a^{2}+4a + 4}{a^{2}+4}}$ (提示:空间向量的夹角公式), 若$a = 0$,则$\sin\theta=\frac{\sqrt{21}}{7}$; 若$a\neq0$,则$\sin\theta=\frac{\sqrt{3}}{\sqrt{7}}\cdot\sqrt{1+\frac{4}{a+\frac{4}{a}}}\leqslant\frac{\sqrt{3}}{\sqrt{7}}\times\sqrt{1+\frac{4}{4}}=\frac{\sqrt{42}}{7}$ (提示:基本不等式的应用), 当且仅当$a=\frac{4}{a}$,即$a = 2$时,等号成立, 所以直线$AN$与平面$A_{1}B_{1}C$所成角的正弦值的最大值为$\frac{\sqrt{42}}{7}$.
18.(17分)
已知$O$为坐标原点,$W$为$\odot O:x^{2}+y^{2}=4$和$\odot M$的公共点,$\overrightarrow{OM}\cdot\overrightarrow{OW}=0$,$\odot M$与直线$x + 2 = 0$相切,记动点$M$的轨迹为$C$.
(Ⅰ)求$C$的方程;
(Ⅱ)若$n>m>0$,直线$l_{1}:x - y - m = 0$与$C$交于点$A$,$B$,直线$l_{2}:x - y - n = 0$与$C$交于点$A'$,$B'$,点$A$,$A'$在第一象限,记直线$AA'$与$BB'$的交点为$G$,直线$AB'$与$BA'$的交点为$H$,线段$AB$的中点为$E$.
(ⅰ)证明:$G$,$E$,$H$三点共线;
(ⅱ)若$(m + 1)^{2}+n = 7$,过点$H$作$l_{1}$的平行线,分别交线段$AA'$,$BB'$于点$T$,$T'$,求四边形$GTET'$面积的最大值.
答案: 轨迹方程 + 直线与抛物线的位置关系 + 基本不等式的应用 【思维导图】(Ⅰ)已知条件\(\xrightarrow{设M(x,y),\odot M与直线x + 2 = 0的切点为N}\vert MN\vert^{2}=\vert MW\vert^{2}=\vert OM\vert^{2}+\vert OW\vert^{2}\to得解\). (Ⅱ)(ⅰ)已知条件\(\to\)设\(\overrightarrow{GA}=\lambda\overrightarrow{GA^{\prime}},\overrightarrow{GB}=\lambda\overrightarrow{GB^{\prime}}(\lambda\neq0)\),记\(A^{\prime}B^{\prime}\)的中点为\(F\to G,E,F\)三点共线\(\xrightarrow{同理}H,E,F\)三点共线\(\to\)得证. (ⅱ)已知条件\(\xrightarrow{设A(x_{1},y_{1}),B(x_{2},y_{2}),A^{\prime}(x_{3},y_{3}),B^{\prime}(x_{4},y_{4})}联立l_{1}与C的方程\to y_{1}+y_{2},y_{1}y_{2}\xrightarrow{同理}y_{3}+y_{4},y_{3}y_{4},y_{F}\xrightarrow{平行线间距离相等}S_{四边形GTET^{\prime}}=S_{四边形GAHB}\to设G(x_{G},2),H(x_{H},2)\to直线AA^{\prime}的方程\to x_{G},x_{H}\to GH\xrightarrow{基本不等式}得解\). 解:(Ⅰ)设\(M(x,y)\),\(\odot M\)与直线\(x + 2 = 0\)的切点为\(N\), 则\(\vert MN\vert^{2}=\vert MW\vert^{2}=\vert OM\vert^{2}+\vert OW\vert^{2}\) (题眼), 所以\(\vert x + 2\vert^{2}=x^{2}+y^{2}+4\), 化简得\(y^{2}=4x\),所以\(C\)的方程为\(y^{2}=4x\). (Ⅱ)(ⅰ)证明:因为\(l_{1}\parallel l_{2}\), 不妨设\(\overrightarrow{GA}=\lambda\overrightarrow{GA^{\prime}},\overrightarrow{GB}=\lambda\overrightarrow{GB^{\prime}}(\lambda\neq0)\), 记\(A^{\prime}B^{\prime}\)的中点为\(F\), 因为\(\overrightarrow{GE}=\frac{1}{2}(\overrightarrow{GA}+\overrightarrow{GB})=\frac{\lambda}{2}(\overrightarrow{GA^{\prime}}+\overrightarrow{GB^{\prime}})=\lambda\overrightarrow{GF}(\lambda\neq0)\) (题眼), 所以\(G,E,F\)三点共线,同理\(H,E,F\)三点共线, 所以\(G,E,H\)三点共线. (ⅱ)设\(A(x_{1},y_{1})\),\(B(x_{2},y_{2})\),\(A^{\prime}(x_{3},y_{3})\),\(B^{\prime}(x_{4},y_{4})\), 联立\(\begin{cases}x - y - m = 0\\y^{2}=4x\end{cases}\)得\(y^{2}-4y - 4m = 0\) (题眼), \(\Delta=16 + 16m\gt0\), 所以\(y_{1}+y_{2}=4\),\(y_{1}y_{2}=-4m\), 所以\(y_{E}=\frac{y_{1}+y_{2}}{2}=2\), 同理\(y_{3}+y_{4}=4\),\(y_{3}y_{4}=-4n\),\(y_{F}=2\), 则\(G,E,H,F\)四点均在定直线\(y = 2\)上. 因为\(TT^{\prime}\parallel l_{1}\),所以\(\triangle EAT\)与\(\triangle EAH\)的面积相等,\(\triangle EBT^{\prime}\)与\(\triangle EBH\)的面积相等(提示:平行线间的距离相等), 所以四边形\(GTET^{\prime}\)的面积等于四边形\(GAHB\)的面积. 设\(G(x_{G},2)\),\(H(x_{H},2)\), 直线\(AA^{\prime}:y - y_{1}=\frac{y_{1}-y_{3}}{x_{1}-x_{3}}(x - x_{1})\), 即\(y - y_{1}=\frac{y_{1}-y_{3}}{\frac{y_{1}^{2}}{4}-\frac{y_{3}^{2}}{4}}(x - \frac{y_{1}^{2}}{4})\), 整理得直线\(AA^{\prime}:y=\frac{4x + y_{1}y_{3}}{y_{1}+y_{3}}\), 又因为\(y_{G}=2\),所以\(x_{G}=\frac{2(y_{1}+y_{3})-y_{1}y_{3}}{4}\), 同理,直线\(BA^{\prime}:y=\frac{4x + y_{2}y_{3}}{y_{2}+y_{3}}\),因为\(y_{H}=2\), 所以\(x_{H}=\frac{2(y_{2}+y_{3})-y_{2}y_{3}}{4}\), 所以\(\vert GH\vert=\vert x_{G}-x_{H}\vert=\vert\frac{(y_{1}-y_{2})(2 - y_{3})}{4}\vert=\vert\frac{(y_{1}-y_{2})(\frac{y_{3}+y_{4}}{2}-y_{3})}{4}\vert=\frac{\vert(y_{1}-y_{2})(y_{3}-y_{4})\vert}{8}\), 所以四边形\(GAHB\)的面积 \(S=\frac{1}{2}\vert GH\vert\cdot\vert y_{1}-y_{2}\vert=\frac{(y_{1}-y_{2})^{2}\cdot\vert y_{3}-y_{4}\vert}{16}=\frac{[(y_{1}+y_{2})^{2}-4y_{1}y_{2}]\cdot\sqrt{(y_{3}+y_{4})^{2}-4y_{3}y_{4}}}{16}=\frac{(16 + 16m)\cdot\sqrt{16 + 16n}}{16}=4\sqrt{(1 + m)^{2}(1 + n)}\leqslant4[\frac{(1 + m)^{2}+1 + n}{2}]=16\) (提示:基本不等式的应用), 当且仅当\((1 + m)^{2}=1 + n\),即\(\begin{cases}m = 1\\n = 3\end{cases}\)时取等号, 所以四边形\(GTET^{\prime}\)面积的最大值为\(16\). 
19.(17分)
记集合$S = \{\{ a_{n}\}\mid$无穷数列$\{ a_{n}\}$中存在有限项不为零,$n\in\mathbf{N}^{*}\}$,对任意$\{ a_{n}\}\in S$,设变换$f(\{ a_{n}\}) = a_{1}+a_{2}x+\cdots+a_{n}x^{n - 1}+\cdots$,$x\in\mathbf{R}$.
定义运算$\otimes$:若$\{ a_{n}\}$,$\{ b_{n}\}\in S$,则$\{ a_{n}\}\otimes\{ b_{n}\}\in S$,$f(\{ a_{n}\}\otimes\{ b_{n}\}) = f(\{ a_{n}\})\cdot f(\{ b_{n}\})$.
(Ⅰ)若$\{ a_{n}\}\otimes\{ b_{n}\}=\{ m_{n}\}$,用$a_{1}$,$a_{2}$,$a_{3}$,$a_{4}$,$b_{1}$,$b_{2}$,$b_{3}$,$b_{4}$表示$m_{4}$;
(Ⅱ)证明:$(\{ a_{n}\}\otimes\{ b_{n}\})\otimes\{ c_{n}\}=\{ a_{n}\}\otimes(\{ b_{n}\}\otimes\{ c_{n}\})$;
(Ⅲ)若$a_{n}=\begin{cases}\frac{(n + 1)^{2}+1}{n(n + 1)},1\leqslant n\leqslant100,\\0,n>100,\end{cases}$
$b_{n}=\begin{cases}(\frac{1}{2})^{203 - n},1\leqslant n\leqslant500,\\0,n>500,\end{cases}$ $\{ d_{n}\}=\{ a_{n}\}\otimes\{ b_{n}\}$,
证明:$d_{200}<\frac{1}{2}$.
答案: 新定义 + 裂项相消法求数列的和 【思维导图】(Ⅰ)已知条件\(\xrightarrow{新定义}得解\). (Ⅱ)已知条件\(\to f(\{ a_{n}\})\cdot f(\{ b_{n}\})\cdot f(\{ c_{n}\})=f((\{ a_{n}\otimes\{ b_{n}\})\otimes\{ c_{n}\})=f(\{ a_{n}\otimes(\{ b_{n}\otimes\{ c_{n}\}))\to得证\). (Ⅲ)已知条件\(\to\{ d_{n}\}\to\{ a_{n}\otimes\{ b_{n}\}=\{ d_{n}\}\to d_{200}\xrightarrow{裂项相消法}得证\). 解:(Ⅰ)因为\(m_{4}x^{3}=(a_{1}b_{4}+a_{2}b_{3}+a_{3}b_{2}+a_{4}b_{1})x^{3}\) (题眼), 所以\(m_{4}=a_{1}b_{4}+a_{2}b_{3}+a_{3}b_{2}+a_{4}b_{1}\). (Ⅱ)证明:因为\(f(\{ a_{n}\otimes\{ b_{n}\})=f(\{ a_{n}\})\cdot f(\{ b_{n}\})\), 所以\(f(\{ a_{n}\})\cdot f(\{ b_{n}\})\cdot f(\{ c_{n}\})=f(\{ a_{n}\otimes\{ b_{n}\})\cdot f(\{ c_{n}\})=f((\{ a_{n}\otimes\{ b_{n}\})\otimes\{ c_{n}\})\). 又因为\(f(\{ a_{n}\})\cdot f(\{ b_{n}\})\cdot f(\{ c_{n}\})=f(\{ a_{n}\})\cdot[f(\{ b_{n}\})\cdot f(\{ c_{n}\})]=f(\{ a_{n}\})\cdot f(\{ b_{n}\otimes\{ c_{n}\})=f(\{ a_{n}\otimes(\{ b_{n}\otimes\{ c_{n}\}))\), 所以\(f((\{ a_{n}\otimes\{ b_{n}\})\otimes f\{ c_{n}\})=f(\{ a_{n}\otimes(\{ b_{n}\otimes f\{ c_{n}\}))\), 所以\((\{ a_{n}\otimes\{ b_{n}\})\otimes\{ c_{n}\}=\{ a_{n}\otimes(\{ b_{n}\otimes\{ c_{n}\})\). (Ⅲ)证明:对于\(\{ a_{n}\},\{ b_{n}\}\in S\), 因为\((a_{1}+a_{2}x+\cdots+a_{n}x^{n - 1}+\cdots)(b_{1}+b_{2}x+\cdots+b_{n}x^{n - 1}+\cdots)=d_{1}+d_{2}x+\cdots+d_{n}x^{n - 1}+\cdots\), 所以\(d_{n}x^{n - 1}=a_{1}(b_{n}x^{n - 1})+a_{2}x(b_{n - 1}x^{n - 2})+\cdots+a_{k}x^{k - 1}\cdot(b_{n + 1 - k}x^{n - k})+\cdots+a_{n - 1}x^{n - 2}(b_{2}x)+a_{n}x^{n - 1}b_{1}\), 所以\(d_{n}=a_{1}b_{n}+a_{2}b_{n - 1}+\cdots+a_{k}b_{n + 1 - k}+\cdots+a_{n - 1}b_{2}+a_{n}b_{1}\), 所以\(\{ a_{n}\otimes\{ b_{n}\}=\{ d_{n}\}=\{\sum_{k = 1}^{n}a_{k}b_{n + 1 - k}\}\) (题眼), \(d_{200}=\sum_{k = 1}^{200}a_{k}b_{201 - k}=\sum_{k = 1}^{100}a_{k}b_{201 - k}+\sum_{k = 101}^{200}a_{k}b_{201 - k}=\sum_{k = 1}^{100}a_{k}b_{201 - k}=\sum_{k = 1}^{100}\frac{(k + 1)^{2}+1}{k(k + 1)2^{k + 2}}\), 所以\(d_{200}=\sum_{k = 1}^{100}\frac{1}{2^{k + 2}}(1+\frac{2}{k}-\frac{1}{k + 1})=\sum_{k = 1}^{100}\frac{1}{2^{k + 2}}+\sum_{k = 1}^{100}[\frac{1}{k\cdot2^{k + 1}}-\frac{1}{(k + 1)\cdot2^{k + 2}}]\) (提示:裂项相消法求数列的和) \(=\frac{1}{2}-\frac{102}{101\times2^{102}}\lt\frac{1}{2}\). (解析人:杜 伟)

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