<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:content="http://purl.org/rss/1.0/modules/content/"><channel><title>春季高考 on 数学之家</title><link>https://www.ydlxsx.top/tags/%E6%98%A5%E5%AD%A3%E9%AB%98%E8%80%83/</link><description>Recent content in 春季高考 on 数学之家</description><generator>Hugo</generator><language>zh-CN</language><copyright>苏ICP备2026047757号 · 苏公网安备32082902023086号</copyright><lastBuildDate>Wed, 02 Sep 2026 15:08:00 +0800</lastBuildDate><atom:link href="https://www.ydlxsx.top/tags/%E6%98%A5%E5%AD%A3%E9%AB%98%E8%80%83/index.xml" rel="self" type="application/rss+xml"/><item><title>2025年上海春季高考数学真题</title><link>https://www.ydlxsx.top/archives/2025%E5%B9%B4%E4%B8%8A%E6%B5%B7%E6%98%A5%E5%AD%A3%E9%AB%98%E8%80%83%E6%95%B0%E5%AD%A6%E7%9C%9F%E9%A2%98/</link><pubDate>Wed, 02 Sep 2026 15:08:00 +0800</pubDate><guid>https://www.ydlxsx.top/archives/2025%E5%B9%B4%E4%B8%8A%E6%B5%B7%E6%98%A5%E5%AD%A3%E9%AB%98%E8%80%83%E6%95%B0%E5%AD%A6%E7%9C%9F%E9%A2%98/</guid><description>2025 年上海春季高考数学试题，含填空 12 题、单选 4 题、解答 5 题，附答案与详解。</description><content:encoded><![CDATA[<h2 id="一填空题">一、填空题</h2>
<p><strong>1.</strong> 已知集合$A = \left\{ x|x > 0 \right\}$，$B = \left\{ - 1,0,1,2 \right\}$，则$A \cap B$等于______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\{ 1,2\}$</p>
<p>【详解】试题分析：$A \cap B = \{ x|x > 0\} \cap \{ - 1,0,1,2\} = \{ 1,2\}$</p>
<p>考点：集合运算</p>
<p>【方法点睛】1.用描述法表示集合，首先要弄清集合中代表元素的含义，再看元素的限制条件，明确集合类型，是数集、点集还是其他的集合．</p>
<p>2．求集合的交、并、补时，一般先化简集合，再由交、并、补的定义求解．</p>
<p>3．在进行集合的运算时要尽可能地借助Venn图和数轴使抽象问题直观化．一般地，集合元素离散时用Venn图表示；集合元素连续时用数轴表示，用数轴表示时要注意端点值的取舍．</p>
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<p><strong>2.</strong> 不等式$\frac{x}{x - 1} < 0$的解集为______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$(0,1)$</p>
<p>【分析】将不等式$\frac{x}{x - 1} < 0$化为$x(x - 1) < 0$，即可得答案.</p>
<p>【详解】由题意得不等式$\frac{x}{x - 1} < 0$即$x(x - 1) < 0,\therefore x \in (0,1)$，</p>
<p>即不等式$\frac{x}{x - 1} < 0$的解集为$(0,1)$，</p>
<p>故答案为：$(0,1)$</p>
</blockquote>
</details>
<p><strong>3.</strong> 已知复数$z = \frac{2 + \mathrm{i}}{\mathrm{i}}$，其中i为虚数单位，则$|z| =$______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\sqrt{5}$</p>
<p>【分析】根据复数的除法运算和复数模的计算公式即可.</p>
<p>【详解】$z = \frac{2 + i}{i} = \frac{i(2 + i)}{i^{2}} = 1 - 2i$，</p>
<p>故$|z| = \sqrt{1^{2} + {( - 2)}^{2}} = \sqrt{5}$．</p>
<p>故答案为：$\sqrt{5}$.</p>
</blockquote>
</details>
<p><strong>4.</strong> 已知$\overrightarrow{a} = (2,1),\overrightarrow{b} = (1,x)$，若$\overrightarrow{a} \parallel \overrightarrow{b}$，则$x =$______．</p>
<details class="ans">
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<blockquote>
<p>【答案】$\frac{1}{2}$/$0.5$</p>
<p>【分析】由平面向量共线的坐标表示即可求解.</p>
<p>【详解】由$\overrightarrow{a} \parallel \overrightarrow{b}$得$2x - 1 = 0$，解得$x = \frac{1}{2}$.</p>
<p>故答案为：$\frac{1}{2}$.</p>
</blockquote>
</details>
<p><strong>5.</strong> 已知$\tan\alpha = 1$，则$\cos\left( \alpha + \frac{\pi}{4} \right) =$______．</p>
<details class="ans">
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<blockquote>
<p>【答案】$0$</p>
<p>【分析】利用同角三角函数关系和余弦的两角和公式求解即可.</p>
<p>【详解】由$\tan\alpha = \frac{\sin\alpha}{\cos\alpha} = 1$可得$\sin\alpha = \cos\alpha$，</p>
<p>所以$\cos\left( \alpha + \frac{\pi}{4} \right) = \cos\alpha\cos\frac{\pi}{4} - \sin\alpha\sin\frac{\pi}{4} = \frac{\sqrt{2}}{2}\left( \cos\alpha - \sin\alpha \right) = 0$，</p>
<p>故答案为：$0$</p>
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<p><strong>6.</strong> 已知$\left( x + \frac{m}{x} \right)^{6}$的展开式中常数项为20，则实数<em>m</em>的值为______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】1</p>
<p>【分析】根据二项式展开式的通项特征可得$\text{C}_{6}^{3}m^{3} = 20$，进而可求解.</p>
<p>【详解】展开式的通项为$\text{C}_{6}^{r}x^{6 - r}\left( \frac{m}{x} \right)^{r} = \text{C}_{6}^{r}m^{r}x^{6 - 2r}$，令$6 - 2r = 0$解得$r = 3$，∴$\text{C}_{6}^{3}m^{3} = 20$．</p>
<p>∴$m = 1$．</p>
<p>故答案为：1</p>
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<p><strong>7.</strong> 已知$\left\{ a_{n} \right\}$是首项为1、公差为1的等差数列，$\left\{ b_{n} \right\}$是首项为1、公比为$q(q > 0)$的等比数列．若数列$\left\{ a_{n} \cdot b_{n} \right\}$的前三项和为2，则$q =$______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\frac{1}{3}$</p>
<p>【分析】写出通项公式，得到$a_{n} \cdot b_{n} = nq^{n - 1}$，从而根据前三项和得到方程，求出公比.</p>
<p>【详解】由题意得$a_{n} = 1 + n - 1 = n$，$b_{n} = q^{n - 1}$，</p>
<p>则$a_{n} \cdot b_{n} = nq^{n - 1}$，所以前三项和为$1 + 2q + 3q^{2} = 2$，</p>
<p>解得$q = \frac{1}{3}$或-1（舍去），</p>
<p>故答案为：$\frac{1}{3}$</p>
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<p><strong>8.</strong> 关于<em>x</em>的方程$|x - 1| + |\pi - x| = \pi - 1$的解集为______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\lbrack 1,\pi\rbrack$</p>
<p>【分析】根据$x$的取值范围去绝对值，分类讨论解方程即可.</p>
<p>【详解】$|x - 1| + |\pi - x| = \left\{ \begin{array}{r} x - 1 + x - \pi,x \geq \pi \\ \pi - 1,1 < x < \pi \\ 1 - x + \pi - x,x \leq 1 \end{array} \right.\ = \left\{ \begin{array}{r} 2x - 1 - \pi,x \geq \pi \\ \pi - 1,1 < x < \pi \\ 1 + \pi - 2x,x \leq 1 \end{array} \right.$.</p>
<p>当$x \geq \pi$时，令$2x - 1 - \pi=\pi - 1$得$x = \pi$；</p>
<p>当$1 < x < \pi$时，$|x - 1| + |\pi - x| = \pi - 1$恒成立；</p>
<p>当$x \leq 1$时，令$1 + \pi - 2x = \pi - 1$得$x = \text{1}$.</p>
<p>综上所述，方程$|x - 1| + |\pi - x| = \pi - 1$的解集为$\lbrack 1,\pi\rbrack$.</p>
<p>故答案为：$\lbrack 1,\pi\rbrack$.</p>
</blockquote>
</details>
<p><strong>9.</strong> 已知<em>P</em>是一个圆锥的顶点，$PA$是母线，$PA = 2$，该圆锥的底面半径是1．<em>B</em>、<em>C</em>分别在圆锥的底面上，则异面直线$PA$与$BC$所成角的最小值为______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\frac{\pi}{3}$</p>
<p>【分析】过$A$作$AD//BC$交底面圆锥于$D$点，则$\angle PAD$为异面直线$PA$与$BC$所成角，结合余弦定理与余弦函数的性质即可得$\angle PAD$的取值范围，从而得所求最值.</p>
<p>【详解】</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145911673.png" alt="image-20260902145911673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>如图，过$A$作$AD//BC$交底面圆锥于$D$点，连接$PD$，</p>
<p>因为$PA = PD,AD//BC$，则$\angle PAD$为异面直线$PA$与$BC$所成角，</p>
<p>所以$\cos\angle PAD = \frac{|PA|^{2} + |AD|^{2} - |PD|^{2}}{2|PA| \cdot |AD|} = \frac{2^{2} + |AD|^{2} - 2^{2}}{4|AD|} = \frac{|AD|}{4}$，</p>
<p>又$0 < |AD| \leq 2$，所以$0 < \frac{|AD|}{4} \leq \frac{1}{2}$，即$0 < \cos\angle PAD \leq \frac{1}{2}$，</p>
<p>因为$\angle PAD \in \left( 0,\frac{\pi}{2} \right)$，函数$y = \cos\alpha$在$\alpha \in \left( 0,\frac{\pi}{2} \right)$上单调递减，所以$\frac{\pi}{3} \leq \angle PAD < \frac{\pi}{2}$，</p>
<p>故异面直线$PA$与$BC$所成角的最小值为$\frac{\pi}{3}$.</p>
<p>故答案为：$\frac{\pi}{3}$.</p>
</blockquote>
</details>
<p><strong>10.</strong> 已知双曲线$\frac{x^{2}}{a^{2}} - \frac{y^{2}}{6 - a^{2}} = 1(a > 0)$的左、右焦点分别为$F_{1}、F_{2}$．通过$F_{2}$且倾斜角为$\frac{\pi}{3}$的直线与双曲线交于第一象限的点<em>A</em>，延长$AF_{2}$至<em>B</em>使得$AB = AF_{1}$．若$\bigtriangleup BF_{1}F_{2}$的面积为$3\sqrt{6}$，则<em>a</em>的值为______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\sqrt{3}$</p>
<p>【分析】由题意作图，根据三角形面积公式以及直线方程，结合双曲线的标准方程，可得答案.</p>
<p>【详解】由题意可作图如下：</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145912673.png" alt="image-20260902145912673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>由$\frac{x^{2}}{a^{2}} - \frac{y^{2}}{6 - a^{2}} = 1$，则$b^{2} = 6 - a^{2} > 0$，解得$0 < a < \sqrt{6}$，且$c = \sqrt{a^{2} + b^{2}} = \sqrt{6}$，</p>
<p>则$F_{1}\left( - \sqrt{6},0 \right)$，$F_{2}\left( \sqrt{6},0 \right)$，</p>
<p>设$B\left( x_{B},y_{B} \right)$，则$S_{\bigtriangleup BF_{1}F_{2}} = \frac{1}{2} \cdot \left| y_{B} \right| \cdot \left| F_{1}F_{2} \right| = \sqrt{6}\left| y_{B} \right| = 3\sqrt{6}$，解得$y_{B} = - 3$，</p>
<p>由题意可得直线$AB$的斜率$\tan\frac{\pi}{3} = \sqrt{3}$，则方程为$y = \sqrt{3}\left( x - \sqrt{6} \right)$，</p>
<p>将$y_{B} = - 3$代入上式，则$- 3 = \sqrt{3}\left( x_{B} - \sqrt{6} \right)$，解得$x_{B} = \sqrt{6} - \sqrt{3}$，</p>
<p>由题意可得$\left| AF_{1} \right| - \left| AF_{2} \right| = |AB| - \left| AF_{2} \right| = \left| BF_{2} \right| = \sqrt{\left( \sqrt{6} - \sqrt{3} - \sqrt{6} \right)^{2} + ( - 3 - 0)^{2}} = 2\sqrt{3}$，</p>
<p>易知$a = \sqrt{3}$.</p>
<p>故答案为：$\sqrt{3}$.</p>
</blockquote>
</details>
<p><strong>11.</strong> 如图所示，正方形$ABCD$是一块边长为$4$的工程用料，阴影部分所示是被腐蚀的区域，其余部分完好，曲线$MN$为以$AD$为对称轴的抛物线的一部分，$DM = DN = 3$．工人师傅现要从完好的部分中截取一块矩形原料$BQPR$，当其面积有最大值时，$AQ$的长为______．</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145913673.png" alt="image-20260902145913673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$\frac{4 + \sqrt{7}}{3}$</p>
<p>【分析】建立平面直角坐标系如图所示，由已知求出抛物线方程，当$AQ \geq 3$时，矩形面积最大时为$4$，当$0 < AQ < 3$，设$AQ = x(0 < x < 3)$，即可得到$S$关于$x$的函数式，利用求导判断单调性，即可得到最值.</p>
<p>【详解】由题知，以$A$为原点，建立平面直角坐标系，如图，</p>
<p>则$M(0,1)$，$N(3,4)$，设$MN$方程为：$y = ax^{2} + b$，</p>
<p>所以$\left\{ \begin{array}{r} 0 + b = 1 \\ 9a + b = 4 \end{array} \right.$，$\left\{ \begin{array}{r} a = \frac{1}{3} \\ b = 1 \end{array} \right.$，$MN$方程为：$y = \frac{1}{3}x^{2} + 1$，</p>
<p>令矩形$BQPR$面积为$S$，</p>
<p>当$AQ \geq 3$时，$S \leq S_{BQNC} = 1 \times 4 = 4$，</p>
<p>当$0 < AQ < 3$，设$AQ = x(0 < x < 3)$，则$P\left( x,\frac{1}{3}x^{2} + 1 \right)$，</p>
<p>所以$S = (4 - x)\left( \frac{1}{3}x^{2} + 1 \right) = - \frac{1}{3}x^{3} + \frac{4}{3}x^{2} - x + 4$，</p>
<p>则$S' = - x^{2} + \frac{8}{3}x - 1 = - \left( x - \frac{4}{3} \right)^{2} + \frac{7}{9}$，</p>
<p>令$S' > 0$，则$\frac{4 - \sqrt{7}}{3} < x < \frac{4 + \sqrt{7}}{3}$，$S$在$\left( \frac{4 - \sqrt{7}}{3},\frac{4 + \sqrt{7}}{3} \right)$上递增，</p>
<p>令$S' < 0$，则$x > \frac{4 + \sqrt{7}}{3}$或$x < \frac{4 - \sqrt{7}}{3}$，$S$在$\left( \frac{4 + \sqrt{7}}{3}, + \infty \right),\left( - \infty,\frac{4 - \sqrt{7}}{3} \right)$上递减，</p>
<p>又$0 < x < 3$，$S(0) = 4$，$S\left( \frac{4 + \sqrt{7}}{3} \right) = \frac{344 + 14\sqrt{7}}{81} > 4$，</p>
<p>所以当$AQ$的长为$\frac{4 + \sqrt{7}}{3}$时，该矩形面积最大.</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145914673.png" alt="image-20260902145914673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>故答案为：$\frac{4 + \sqrt{7}}{3}$</p>
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</details>
<p><strong>12.</strong> 在平面中，$\overrightarrow{e_{1}}$和$\overrightarrow{e_{\text{2}}}$是互相垂直的单位向量，向量$\overrightarrow{a}$满足$\left| \overrightarrow{a} - 4\overrightarrow{e_{1}} \right| = 2$，向量$\overrightarrow{b}$满足$\left| \overrightarrow{b} - 6\overrightarrow{e_{2}} \right| = 1$，求$\overrightarrow{b}$在$\overrightarrow{a}$方向上的数量投影的最大值______．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】$4$</p>
<p>【分析】设$\overrightarrow{OA} = \overrightarrow{a},\overrightarrow{OB} = \overrightarrow{b}$，根据题意，求得$A,B$所在圆的圆心和半径；再根据数量投影的意义，数形结合即可求得结果.</p>
<p>【详解】根据题意不妨设$\overrightarrow{e_{1}}$ $= (1,0)$，$\overrightarrow{e_{\text{2}}}$ $= (0,1)$，$\overrightarrow{a}$ $= (x,y)$，$\overrightarrow{b}$ $= (m,n)$，</p>
<p>则$\overrightarrow{a} - 4\overrightarrow{e_{1}} = (x - 4,y),\overrightarrow{b} - 6\overrightarrow{e_{2}} = (m,n - 6)$，</p>
<p>由$\left| \overrightarrow{a} - 4\overrightarrow{e_{1}} \right| = 2$可得$(x - 4)^{2} + y^{2} = 4$，由$\left| \overrightarrow{b} - 6\overrightarrow{e_{2}} \right| = 1$可得$m^{2} + (n - 6)^{2} = 1$；</p>
<p>设$\overrightarrow{OA} = \overrightarrow{a},\overrightarrow{OB} = \overrightarrow{b}$，故$A$在以$C_{1}(4,0)$为圆心，$2$为半径的圆上；</p>
<p>$B$在以$C_{2}(0,6)$为圆心，1为半径的圆上；</p>
<p>过$B$作$BD\bot OA$于$D$，则$OD$即为$\overrightarrow{b}$在$\overrightarrow{a}$上的数量投影，如下所示：</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145915673.png" alt="image-20260902145915673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>因为$A,B$分别为两圆上任意动点，不妨固定$B$，则$OB$为定长，</p>
<p>设$\left\langle \overrightarrow{a},\overrightarrow{b} \right\rangle = \theta$，即$\angle AOB = \theta$，故$|OD| = |OB| \cdot \cos\theta$，</p>
<p>因为此时$|OB|$为定长，且$\theta = \angle AOB < 180{^\circ}$，</p>
<p>故随着$\theta$的减小，$\cos\theta$增大，直至$OA$恰好与圆$C_{1}$相切时，$|OD|$取得最大值，如下所示：</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145916673.png" alt="image-20260902145916673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>在$OA$与圆$C_{1}$相切的基础上，移动点$B$，过$C_{2}$作$C_{2}E\bot OA$于$E$，故$|OD| = |OE| + |ED|$；</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145917673.png" alt="image-20260902145917673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>在△$C_{1}AO$中，$\angle C_{1}AO = 90{^\circ}$，$C_{1}A = 2,OC_{1} = 4$，</p>
<p>故$\angle AOC_{1} = 30{^\circ},\angle C_{2}OE = 60{^\circ}$，因为$\left| OC_{2} \right| = 6$,</p>
<p>故在直角三角形$C_{2}OE$中，$\left| OC_{2} \right| = 2|OE|$，则$OE = 3$，即$|OD| = |OE| + |ED| = 3 + |ED|$；</p>
<p>在四边形$BDEC_{2}$中，因为$\angle DEC_{2} = \angle C_{2}ED = 90{^\circ}$，故$|DE| \leq \left| BC_{2} \right| = 1$，</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145918673.png" alt="image-20260902145918673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>当且仅当$BC_{2}//$ $DE$时等号成立，从而$|OD| = 3 + |ED| \leq 3 + 1 = 4$.</p>
<p>综上所述：$\overrightarrow{b}$在$\overrightarrow{a}$方向上的数量投影的最大值为$4$.</p>
<p>故答案为：$4$.</p>
<p>【点睛】关键点点睛：处理本题的关键，一是熟悉数量投影的几何意义；二是对两个运动的点$A,B$，采用一定一动的处理策略，从而求解最大值.</p>
</blockquote>
</details>
<h2 id="二单选题">二、单选题</h2>
<p><strong>13.</strong> 如图，$ABCD - A_{1}B_{1}C_{1}D_{1}$是正四棱台，则下列各组直线中属于异面直线的是（   ）．</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145919673.png" alt="image-20260902145919673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<ul>
<li>A. $AB$和$C_{1}D_{1}$</li>
<li>B. $AA_{1}$和$CC_{1}$</li>
<li>C. $BD_{1}$和$B_{1}D$</li>
<li>D. $A_{1}D_{1}$和$AB$．</li>
</ul>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】D</p>
<p>【分析】根据棱台的性质及直线与直线的位置关系即可判断.</p>
<p>【详解】因为$ABCD - A_{1}B_{1}C_{1}D_{1}$是正四棱台，所以$AB//A_{1}B_{1}//C_{1}D_{1}$，故A错误，</p>
<p>侧棱延长交于一点，所以$AA_{1}$与$CC_{1}$相交，故B错误，</p>
<p>同理$BB_{1}$与$DD_{1}$也相交，所以$B,B_{1},D_{1},D$四点共面，所以$BD_{1}$与$B_{1}D$相交，故C错误，</p>
<p>$A_{1}D_{1}$与$AB$是异面直线，故D正确.</p>
<p>故选：D</p>
</blockquote>
</details>
<p><strong>14.</strong> 幂函数$y = x^{a}$在$(0, + \infty)$上是严格减函数，且经过$( - 1, - 1)$，则$a$的值可能是（   ）．</p>
<ul>
<li>A. $- \frac{2}{3}$</li>
<li>B. $- \frac{1}{3}$</li>
<li>C. $\frac{1}{3}$</li>
<li>D. 3</li>
</ul>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】B</p>
<p>【分析】根据幂函数的单调性可排除C和D；根据幂函数过点$( - 1, - 1)$，可排除A.</p>
<p>【详解】因为幂函数$y = x^{a}$在$(0, + \infty)$上是严格减函数，所以$a < 0$，故C错误，D错误；</p>
<p>对于A，若$a = - \frac{2}{3}$，则$y = x^{- \frac{2}{3}}$，当$x = - 1$时，$y = ( - 1)^{- \frac{2}{3}} = \frac{1}{( - 1)^{\frac{2}{3}}} = \frac{1}{\sqrt[3]{( - 1)^{2}}} = 1$，</p>
<p>所以幂函数$y = x^{- \frac{2}{3}}$过点$( - 1,1)$，故A错误；</p>
<p>对于B，若$a = - \frac{1}{3}$，则$y = x^{- \frac{1}{3}}$，当$x = - 1$时，$y = ( - 1)^{- \frac{1}{3}} = \frac{1}{( - 1)^{\frac{1}{3}}} = - 1$，</p>
<p>所以幂函数$y = x^{- \frac{1}{3}}$过点$( - 1, - 1)$，故B正确.</p>
<p>故选：B.</p>
</blockquote>
</details>
<p><strong>15.</strong> 有一四边形$ABCD$，对于其四边$AB、BC、CD、DA$，按顺序分别抛掷一枚质量均匀的硬币：如硬币正面朝上，则将其擦去；如硬币反面朝上，则不擦去．最后，以<em>A</em>为起点沿着尚未擦去的边出发，可以到达<em>C</em>点的概率为（   ）．</p>
<ul>
<li>A. $\frac{1}{2}$</li>
<li>B. $\frac{7}{16}$</li>
<li>C. $\frac{1}{4}$</li>
<li>D. $\frac{3}{16}$</li>
</ul>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】B</p>
<p>【分析】根据分步计数原理及古典概型的概率公式求解即可.</p>
<p>【详解】根据题意，对于其四边$AB、BC、CD、DA$，按顺序分别抛掷一枚质量均匀的硬币，</p>
<p>共有$2 \times 2 \times 2 \times 2 = 16$种情况，</p>
<p>要从<em>A</em>出发沿着尚未擦去的边能到达点<em>C</em>，</p>
<p>若保留$AB,BC$两条边，则$CD,DA$可保留也可擦去，</p>
<p>共有$2 \times 2 = 4$种情况；</p>
<p>若保留$AD,DC$两条边，则$AB,BC$可保留也可擦去，</p>
<p>共有$2 \times 2 - 1 = 3$种情况（其中有一种情况与上面重复），</p>
<p>则要从<em>A</em>出发沿着尚未擦去的边能到达点<em>C</em>，共有$7$种情况，</p>
<p>所以可以到达<em>C</em>点的概率为$\frac{7}{16}$.</p>
<p>故选：B.</p>
</blockquote>
</details>
<p><strong>16.</strong> 已知$a \in \mathbf{R}$，不等式$\left\lbrack \tan\left( \frac{\pi}{6}x \right) - a \right\rbrack\left\lbrack \tan\left( \frac{\pi}{6}x \right) - a - 1 \right\rbrack < 0$在$(0,2025)$中的整数解有<em>m</em>个．关于<em>m</em>的个数，以下不可能的是（   ）．</p>
<ul>
<li>A. 0</li>
<li>B. 338</li>
<li>C. 674</li>
<li>D. 1012</li>
</ul>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】D</p>
<p>【分析】由题设可得$a < \tan\left( \frac{\pi}{6}x \right) < a + 1$，结合正切函数的周期分$a \leq - \sqrt{3}$或$a \geq \sqrt{3}$时，和$- \sqrt{3} < a < \sqrt{3}$两种情况讨论求解即可.</p>
<p>【详解】由$\left\lbrack \tan\left( \frac{\pi}{6}x \right) - a \right\rbrack\left\lbrack \tan\left( \frac{\pi}{6}x \right) - a - 1 \right\rbrack < 0$，即$a < \tan\left( \frac{\pi}{6}x \right) < a + 1$，</p>
<p>对于$f(x) = \tan\left( \frac{\pi}{6}x \right)$，周期为$T = 6$，</p>
<p>且$f(0) = 0,f(1) = \frac{\sqrt{3}}{3},f(2) = \sqrt{3}$，$f(4) = - \sqrt{3},f(5) = - \frac{\sqrt{3}}{3},f(6) = 0$，</p>
<p>当$a \leq - \sqrt{3}$或$a \geq \sqrt{3}$时，不等式$a < \tan\left( \frac{\pi}{6}x \right) < a + 1$在$(0,2025)$中无整数解；</p>
<p>当$- \sqrt{3} < a < \sqrt{3}$时，若不等式$a < \tan\left( \frac{\pi}{6}x \right) < a + 1$有在$(0,6\rbrack$内只有1个整数解，</p>
<p>比如$a = 1$时，此时在$(0,6\rbrack$内的整数解为$x = 2$，</p>
<p>而$2025 = 6 \times 337 + 3$，</p>
<p>则在$(0,2025)$中可能有$337 + 1 = 338$个整数解；</p>
<p>若不等式$a < \tan\left( \frac{\pi}{6}x \right) < a + 1$有在$(0,6\rbrack$内只有2个整数解，</p>
<p>比如$a = - 0.9$时，此时在$(0,6\rbrack$内的整数解为$x = 5$或$x = 6$，</p>
<p>则在$(0,2025)$中可能有$337 \times 2 = 674$个整数解；</p>
<p>由于$\left| \frac{\sqrt{3}}{3} - 1 \right| < 1,\left| \sqrt{3} - \frac{\sqrt{3}}{3} \right| > 1,\left| - \sqrt{3} - \left( - \frac{\sqrt{3}}{3} \right) \right| > 1,\left| - \frac{\sqrt{3}}{3} - ( - 1) \right| < 1$，</p>
<p>则在$(0,6\rbrack$内最多只有2个整数解，因此在$(0,2025)$中不可能有1012个整数解.</p>
<p>故选：D.</p>
</blockquote>
</details>
<h2 id="三解答题">三、解答题</h2>
<p><strong>17.</strong> 在三棱锥$P - ABC$中，平面$PAC\bot$平面$ABC$，$PA = AC = CP = 2$，$AB = BC = \sqrt{2}$，</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145920673.png" alt="image-20260902145920673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>(1)若<em>O</em>是棱$AC$的中点，证明：$BO\bot$平面$PAC$，并求三棱锥$B - OPA$的体积；</p>
<p>(2)求二面角$B - PC - A$的大小．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】(1)连接$BO$，因为$AB = BC = \sqrt{2}$，所以$BO$⊥$AC$，</p>
<p>因为平面$PAC\bot$平面$ABC$，交线为$AC$，</p>
<p>$BO \subset$平面$ABC$，</p>
<p>所以$BO$⊥平面$PAC$，</p>
<p>体积为$\frac{\sqrt{3}}{6}$</p>
<p>(2)$\arccos\frac{\sqrt{21}}{7}$</p>
<p>【分析】（1）作出辅助线，得到线线垂直，根据面面垂直，得到线面垂直，并利用锥体体积公式求出答案；</p>
<p>（2）证明出$OB,OC,OP$两两垂直，建立空间直角坐标系，求出两个平面的法向量，求出$\cos\overrightarrow{m},\overrightarrow{n} = \frac{\overrightarrow{m} \cdot \overrightarrow{n}}{|\overrightarrow{m}| \cdot |\overrightarrow{n}|} = \frac{\sqrt{21}}{7}$，进而求出二面角$B - PC - A$的大小.</p>
<p>【详解】（1）因为$PA = AC = CP = 2$，所以$PO$⊥$AC$，$AO = 1$，$PO = \sqrt{AP^{2} - AO^{2}} = \sqrt{3}$，</p>
<p>故$S_{\bigtriangleup OPA} = \frac{1}{2}OP \cdot AO = \frac{1}{2} \times \sqrt{3} \times 1 = \frac{\sqrt{3}}{2}$，</p>
<p>$AB = \sqrt{2}$，由勾股定理得$BO = \sqrt{AB^{2} - AO^{2}} = \sqrt{2 - 1} = 1$，</p>
<p>又$BO$⊥平面$PAC$，</p>
<p>三棱锥$B - OPA$的体积$V = \frac{1}{3}S_{\bigtriangleup OPA} \cdot BO = \frac{1}{3} \times \frac{\sqrt{3}}{2} \times 1 = \frac{\sqrt{3}}{6}$；</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145921673.png" alt="image-20260902145921673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>（2）由（1）知，$BO$⊥平面$PAC$，$OC,OP \subset$平面$PAC$，</p>
<p>所以$BO$⊥$OC$，$BO$⊥$OP$，又$PO$⊥$AC$，故$OB,OC,OP$两两垂直，</p>
<p>以$O$为坐标原点，$OB,OC,OP$所在直线分别为$x,y,z$轴，建立空间直角坐标系，</p>
<p>则$B(1,0,0),P(0,0,\sqrt{3}),C(0,1,0),A(0, - 1,0)$，</p>
<p>$\overrightarrow{BP} = ( - 1,0,\sqrt{3}),\overrightarrow{PC} = (0,1, - \sqrt{3})$，</p>
<p>设平面$BPC$的一个法向量为$\overrightarrow{m} = (x,y,z)$，</p>
<p>则$\{\begin{array}{r} \overrightarrow{m} \cdot \overrightarrow{BP} = (x,y,z) \cdot ( - 1,0,\sqrt{3}) = - x + \sqrt{3}z = 0 \\ \overrightarrow{m} \cdot \overrightarrow{PC} = (x,y,z) \cdot (0,1, - \sqrt{3}) = y - \sqrt{3}z = 0 \end{array}$，</p>
<p>令$z = 1$得$x = y = \sqrt{3}$，故$\overrightarrow{m} = (\sqrt{3},\sqrt{3},1)$，</p>
<p>又平面$PCA$的一个法向量为$\overrightarrow{n} = (1,0,0)$，</p>
<p>故$\cos\langle\overrightarrow{m},\overrightarrow{n}\rangle = \frac{\overrightarrow{m} \cdot \overrightarrow{n}}{|\overrightarrow{m}| \cdot |\overrightarrow{n}|} = \frac{(\sqrt{3},\sqrt{3},1) \cdot (1,0,0)}{\sqrt{3 + 3 + 1}} = \frac{\sqrt{3}}{\sqrt{7}} = \frac{\sqrt{21}}{7}$，</p>
<p>由图可知，二面角$B - PC - A$为锐角，</p>
<p>故二面角$B - PC - A$的大小为$\arccos\frac{\sqrt{21}}{7}$.</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145922673.png" alt="image-20260902145922673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
</blockquote>
</details>
<p><strong>18.</strong> 在$\bigtriangleup ABC$中，角<em>A</em>、<em>B</em>、<em>C</em>所对的边分别为<em>a</em>、<em>b</em>、<em>c</em>，且$c = 5$．</p>
<p>(1)若$\frac{a}{4b} = \frac{\sin B}{\sin A},C = \frac{\pi}{2}$，求<em>a</em>；</p>
<p>(2)若$ab = 20$，求$\bigtriangleup ABC$的面积的最大值．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】(1)$a = 2\sqrt{5}$</p>
<p>(2)$\frac{5\sqrt{55}}{4}$</p>
<p>【分析】（1）由正弦定理角化边结合勾股定理求解即可；</p>
<p>（2）由三角形的面积公式结合余弦定理求解即可；</p>
<p>【详解】（1）由正弦定理可得$\frac{a}{4b} = \frac{\sin B}{\sin A} = \frac{b}{a},$即$a = 2b$，</p>
<p>又$C = \frac{\pi}{2}$，所以$a^{2} + b^{2} = c^{2} = 25$，即$5b^{2} = 25$，解得$b = \sqrt{5}$，</p>
<p>所以$a = 2\sqrt{5}$.</p>
<p>（2）因为$S_{\bigtriangleup ABC} = \frac{1}{2}ab\sin C = 10\sin C$，且$ab = 20$，$c = 5$，</p>
<p>所以$\cos C = \frac{a^{2} + b^{2} - c^{2}}{2ab} \geq \frac{2ab - 25}{2ab} = \frac{3}{8}$，当且仅当$a = b = 2\sqrt{5}$时等号成立，</p>
<p>当$\cos C$取最小值时，$\sin C$取最大值，最大值$\left( \sin C \right)_{\max} = \sqrt{1 - \left( \frac{3}{8} \right)^{2}} = \frac{\sqrt{55}}{8}$，</p>
<p>所以$\bigtriangleup ABC$的面积的最大值为$\frac{5\sqrt{55}}{4}$.</p>
</blockquote>
</details>
<p><strong>19.</strong> 甲、乙是两个体育社团的小组．如下是两组组员身高的茎叶图（单位：厘米），以身高的百位数和十位数作为&quot;茎&quot;排列在中间、个位数作为&quot;叶&quot;分列在两边．</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145923673.png" alt="image-20260902145923673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>(1)分别求甲、乙两组组员身高的第60百分位数；</p>
<p>(2)从甲、乙两组各选取一个组员，求两人身高均在170厘米以上的概率；</p>
<p>(3)为使两组人数相同，从甲组中调派一个队员到乙组．是否存在甲组的一个组员，将他调派至乙组后，甲、乙两组的平均身高都增大？</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】(1)甲组第60百分位数为173 厘米，乙组第60百分位数为$166.5$厘米；</p>
<p>(2)$\frac{7}{120}$；</p>
<p>(3)把甲组的其中一个167厘米的组员调到乙组.</p>
<p>【分析】（1）直接利用百分位数计算公式即可；</p>
<p>（2）根据组合公式和古典概率公式计算即可；</p>
<p>（3）求出两者平均数，则所调的人员身高应该两平均数之间（不包括两平均数）.</p>
<p>【详解】（1）甲队：$i = 12 \times 60\% = 7.2$，</p>
<p>所以甲组的第60百分位数为从小到大排列的第8位组员身高，为173厘米；</p>
<p>乙队：$i = 10 \times 60\% = 6$，</p>
<p>所以乙组的第60百分位数为从小到大排列第6位和第7位组员身高的平均数，为$\frac{166 + 167}{2} = 166.5$厘米．</p>
<p>（2）记甲乙两队各选取一名组员，两人身高均在170厘米以上为事件$A$，</p>
<p>$P(A) = \frac{n(A)}{n(\Omega)} = \frac{C_{7}^{1} \cdot C_{1}^{1}}{C_{12}^{1} \cdot C_{10}^{1}} = \frac{7}{120}$.</p>
<p>（3）$\overline{x_{甲}} = \frac{167 \times 2 + 165 \times 2 + 164 + 178 + 175 + 174 + 173 + 172 \times 2 + 183}{12} = 171.25$，</p>
<p>$\overline{x_{乙}} = \frac{159 + 160 + 163 + 165 \times 2 + 166 + 167 + 168 \times 2 + 172}{10} = 165.3$</p>
<p>要使两组平均身高都增大，</p>
<p>则从甲组调到乙组的组员身高应在两平均数之间（不包括端点平均数），所以把甲组的其中一个167厘米的组员调到乙组即可．</p>
</blockquote>
</details>
<p><strong>20.</strong> 在平面直角坐标系中，已知曲线$\Gamma:\frac{x^{2}}{4} + y^{2} = 1(y \geq 0)$，点<em>P</em>、<em>Q</em>分别为$\Gamma$上不同的两点，$T(t,0)$．</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145924673.png" alt="image-20260902145924673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>(1)求$\Gamma$所在椭圆的离心率；</p>
<p>(2)若$T(1,0),Q$在<em>y</em>轴上，若<em>T</em>到直线$PQ$的距离为$\frac{\sqrt{5}}{5}$，求<em>P</em>的坐标；</p>
<p>(3)是否存在<em>t</em>，使得$\bigtriangleup TPQ$是以<em>T</em>为直角顶点的等腰直角三角形？若存在，求<em>t</em>的取值范围；若不存在，请说明理由．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】(1)$\frac{\sqrt{3}}{2}$；</p>
<p>(2)$P(2,0)$；</p>
<p>(3)存在，$t \in \lbrack - \frac{6}{5},\frac{6}{5}\rbrack$.</p>
<p>【分析】（1）根据椭圆方程直接求离心率；</p>
<p>（2）问题化为以$T(1,0)$为圆心，$\frac{\sqrt{5}}{5}$为半径的圆与过$Q(0,1)$的直线相切，且切线与$\Gamma:\frac{x^{2}}{4} + y^{2} = 1(y \geq 0)$有交点，设切线方程，利用与圆相切关系求参数，进而确定<em>P</em>的坐标；</p>
<p>（3）设$PQ:y = kx + m$，$P(x_{1},y_{1}),Q(x_{2},y_{2})$，联立椭圆方程，结合韦达定理、判别式得$\sqrt{4k^{2} + 1} > m > 2|k| \geq 0$，注意讨论$k = 0$、$k \neq 0$，确定$PQ$中点为$A( - \frac{4km}{1 + 4k^{2}},\frac{m}{1 + 4k^{2}})$，再结合$k_{TA} = - \frac{1}{k}$、$\overrightarrow{TP} \cdot \overrightarrow{TQ} = 0$求参数范围.</p>
<p>【详解】（1）由$\Gamma:\frac{x^{2}}{4} + y^{2} = 1(y \geq 0)$，则$a = 2,c = \sqrt{3}$，即离心率为$\frac{\sqrt{3}}{2}$；</p>
<p>（2）由题设，问题化为以$T(1,0)$为圆心，$\frac{\sqrt{5}}{5}$为半径的圆与过$Q(0,1)$的直线相切，</p>
<p>且切线与$\Gamma:\frac{x^{2}}{4} + y^{2} = 1(y \geq 0)$有交点，显然切线斜率存在，令切线为$y = nx + 1$，</p>
<p>所以$\frac{|n + 1|}{\sqrt{1 + n^{2}}} = \frac{\sqrt{5}}{5}$，可得$2n^{2} + 5n + 2 = (2n + 1)(n + 2) = 0$，则$n = - \frac{1}{2}$或$n = - 2$，</p>
<p>当$n = - \frac{1}{2}$，则切线为$y = - \frac{1}{2}x + 1$，联立$x^{2} + 4y^{2} = 4$，可得$x^{2} - 2x = 0$，</p>
<p>则$x = 0$或$x = 2$，故此时$P(2,0)$，满足；</p>
<p>当$n = - 2$，则切线为$y = - 2x + 1$，联立$x^{2} + 4y^{2} = 4$，可得$17x^{2} - 16x = 0$，</p>
<p>则$x = 0$或$x = \frac{16}{17}$，故此时$P(\frac{16}{17}, - \frac{15}{17})$，不满足；</p>
<p>综上，$P(2,0)$.</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145925673.png" alt="image-20260902145925673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>（3）由题设，直线$PQ$的斜率存在，可设$PQ:y = kx + m$，$P(x_{1},y_{1}),Q(x_{2},y_{2})$，</p>
<p>联立$x^{2} + 4y^{2} = 4$，整理得$(1 + 4k^{2})x^{2} + 8kmx + 4m^{2} - 4 = 0$，</p>
<p>其中$\Delta = 64k^{2}m^{2} - 16(m^{2} - 1)(1 + 4k^{2}) = 64k^{2} - 16m^{2} + 16 > 0$，即$4k^{2} > m^{2} - 1$，</p>
<p>所以$x_{1} + x_{2} = - \frac{8km}{1 + 4k^{2}}$，$x_{1}x_{2} = \frac{4(m^{2} - 1)}{1 + 4k^{2}}$，则$y_{1} + y_{2} = k(x_{1} + x_{2}) + 2m = \frac{2m}{1 + 4k^{2}} > 0$，</p>
<p>$y_{1}y_{2} = k^{2}x_{1}x_{2} + km\left( x_{1} + x_{2} \right) + m^{2} = \frac{4k^{2}m^{2} - 4k^{2}}{1 + 4k^{2}} - \frac{8k^{2}m^{2}}{1 + 4k^{2}} + m^{2} = \frac{m^{2} - 4k^{2}}{1 + 4k^{2}} \geq 0$，</p>
<p>所以$m^{2} \geq 4k^{2}$且$m > 0$，故$\sqrt{4k^{2} + 1} > m > 2|k| \geq 0$，</p>
<p>当$k = 0$时，则$y_{1} = y_{2} = m$且$|x_{1}| = |x_{2}| = m$，则$m = \frac{2\sqrt{5}}{5} \in (0,1)$，此时$T(0,0)$，满足；</p>
<p>当$k \neq 0$，而$PQ$的中点为$A( - \frac{4km}{1 + 4k^{2}},\frac{m}{1 + 4k^{2}})$，又$T(t,0)$，</p>
<p>则$k_{TA} = \frac{\frac{m}{1 + 4k^{2}} - 0}{- \frac{4km}{1 + 4k^{2}} - t} = - \frac{1}{k}$，即$t = - \frac{3km}{1 + 4k^{2}}$，</p>
<p>且$\overrightarrow{TP} \cdot \overrightarrow{TQ} = (x_{1} - t)(x_{2} - t) + y_{1}y_{2} = x_{1}x_{2} - t(x_{1} + x_{2}) + t^{2} + y_{1}y_{2} = 0$，</p>
<p>$\frac{4(m^{2} - 1)}{1 + 4k^{2}} + \frac{8kmt}{1 + 4k^{2}} + t^{2} + \frac{m^{2} - 4k^{2}}{1 + 4k^{2}} = \frac{5m^{2} - 4k^{2} - 4}{1 + 4k^{2}} + \frac{8kmt}{1 + 4k^{2}} + t^{2} = 0$，</p>
<p>所以$5m^{2} - 4k^{2} - 4 + 8kmt + (1 + 4k^{2})t^{2} = 0$，则$5m^{2}(1 + k^{2}) = 4(4k^{4} + 5k^{2} + 1)$，</p>
<p>所以$m^{2} = \frac{4}{5}(4k^{2} + 1)$，则$\frac{4}{5}(4k^{2} + 1) \geq 4k^{2} \Rightarrow 0 < k^{2} \leq 1$，故$t^{2} = \frac{9k^{2}m^{2}}{{(1 + 4k^{2})}^{2}} = \frac{36}{\frac{5}{k^{2}} + 20}$</p>
<p>所以$t^{2} \in (0,\frac{36}{25}\rbrack$，则$t \in \lbrack - \frac{6}{5},0) \cup (0,\frac{6}{5}\rbrack$.</p>
<p>综上，$t \in \lbrack - \frac{6}{5},\frac{6}{5}\rbrack$.</p>
<img src="/posts/2025年上海春季高考数学真题/image-20260902145926673.png" alt="image-20260902145926673" style="zoom:20%; display:block; margin-left:0; margin-right:auto;" />
<p>【点睛】关键点点睛：第三问，设$PQ:y = kx + m$，$P(x_{1},y_{1}),Q(x_{2},y_{2})$，根据已知得到$\sqrt{4k^{2} + 1} > m > 2|k| > 0$，且$k_{TA} = - \frac{1}{k}$、$\overrightarrow{TP} \cdot \overrightarrow{TQ} = 0$的应用为关键</p>
</blockquote>
</details>
<p><strong>21.</strong> 已知函数$y = f(x)$的定义域是$D$．对于$t \in D$，定义集合$S_{f(t)} = \left\{ x\left| f(x) \geq f(t) \right.\ \right\}$．</p>
<p>(1)$f(x) = \log_{2}x$，求$S_{f(16)}$；</p>
<p>(2)对于集合$A$，若对任意$x \in A$都有$- x \in A$，则称$A$是对称集．若$D$是对称集，证明：&ldquo;函数$y = f(x)$是偶函数&quot;的充要条件是&quot;对任意$t \in D$，$S_{f(t)}$是对称集&rdquo;；</p>
<p>(3)若$x \in R$，$f(x) = \mathrm{e}^{x} - \frac{1}{2}mx^{2}$．求$m$的取值范围，使得对于任意$t_{1} < t_{2} \in D$，都有$S_{f\left( t_{2} \right)} \subseteq S_{f\left( t_{1} \right)}$．</p>
<details class="ans">
<summary>查看答案与解析</summary>
<blockquote>
<p>【答案】(1)$\left\{ x\left| x \geq 16 \right.\ \right\}$</p>
<p>（2）</p>
<p>证明：必要性：因为函数$y = f(x)$是偶函数，所以对任意$x \in D$，$f(x) = f( - x)$，</p>
<p>对任意$t \in D$，若$x \in S_{f(t)}$，即$f(x) \geq f(t)$，则$f( - x) = f(x) \geq f(t)$，</p>
<p>所以$- x \in S_{f(t)}$，所以对任意$t \in D$，$S_{f(t)}$是对称集.</p>
<p>充分性：若对任意$t \in D$，$S_{f(t)}$是对称集，</p>
<p>因为对任意$t \in D$，$t \in S_{f(t)}$，所以$- t \in S_{f(t)}$，即$f( - t) \geq f(t)$①，</p>
<p>又$- t \in S_{f( - t)}$，所以$t \in S_{f( - t)}$，即$f(t) \geq f( - t)$②.</p>
<p>由①②得，对任意$t \in D$，$f(t) = f( - t)$，</p>
<p>所以函数$y = f(x)$是偶函数.</p>
<p>综上，&ldquo;函数$y = f(x)$是偶函数&quot;的充要条件是&quot;对任意$t \in D$，$S_{f(t)}$是对称集&rdquo;，得证.</p>
<p>(3)$\left\lbrack 0,\mathrm{e} \right\rbrack$</p>
<p>【分析】（1）根据对数函数的单调性即可求解；</p>
<p>（2）根据偶函数的定义和对称集的定义即可证明必要性和充分性；</p>
<p>（3）根据定义判断出函数单调不减，得到导函数大于等于0恒成立即可求解.</p>
<p>【详解】（1）由定义得，$S_{f(16)} = \left\{ x\left| f(x) \geq f(16) \right.\ \right\} = \left\{ x\left| \log_{2}x \geq \log_{2}16 \right.\ \right\} = \left\{ x\left| x \geq 16 \right.\ \right\}$.</p>
<p>（2）略</p>
<p>（3）因为对于任意$t_{1} < t_{2} \in D$，都有$S_{f\left( t_{2} \right)} \subseteq S_{f\left( t_{1} \right)}$，</p>
<p>所以若$x \in S_{f\left( t_{2} \right)}$，则$x \in S_{f\left( t_{1} \right)}$，即若$f(x) \geq f\left( t_{2} \right)$，则$f(x) \geq f\left( t_{1} \right)$，</p>
<p>所以$f\left( t_{2} \right) \geq f\left( t_{1} \right)$，所以$f(x)$在$\mathbf{R}$上单调不减，</p>
<p>所以对任意$x \in \mathbf{R}$，$f'(x) = \mathrm{e}^{x} - mx \geq 0$恒成立.</p>
<p>当$x = 0$时，显然成立，$m \in \mathbf{R}$；</p>
<p>当$x > 0$时，$m \leq \frac{\mathrm{e}^{x}}{x}$恒成立，令$g(x) = \frac{\mathrm{e}^{x}}{x}$，$g'(x) = \frac{(x - 1)\mathrm{e}^{x}}{x^{2}}$，</p>
<p>所以$g(x)$在$(0,1)$单调递减，$(1, + \infty)$单调递增，所以$m \leq g(x)_{\min} = g(1) = \mathrm{e}$；</p>
<p>当$x < 0$时，$m \geq \frac{\mathrm{e}^{x}}{x}$恒成立，此时$g'(x) = \frac{(x - 1)\mathrm{e}^{x}}{x^{2}} < 0$</p>
<p>因为$g(x)$在$( - \infty,0)$上单调递减，当$x \rightarrow - \infty$时，$g(x) \rightarrow 0,g(x) < 0$，</p>
<p>$x < 0,x \rightarrow 0$时，$g(x) \rightarrow - \infty$，</p>
<p>所以$m \geq 0$；</p>
<p>综上，$m \in \left\lbrack 0,\mathrm{e} \right\rbrack$.</p>
<p>【点睛】关键点点睛：函数在区间上单调不减等价于导函数在区间上大于等于0恒成立.</p>
</blockquote>
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