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  2. <p>湖南省长郡中学2019-2020学年高一数学上学期模块检测试题(含解析)</p>
  3. <p>一、选择题(共12小题,每小题3分,共36分)</p>
  4. <p>1.已知全集U=R,集合<img src="files/image1.png" width="232px" height="29px" data-latex="$A=\left\{ x\left| 0\le x\le 2 \right. \right\},B=\{x\left| {{x}^{2}} \right.-x>0\}$" />,则图中的阴影部分表示的集合为(  )</p>
  5. <p><img src="files/image2.png" width="119px" height="69px" /></p>
  6. <p>A. <img src="files/image3.png" width="109px" height="21px" data-latex="$$" />B. <img src="files/image4.png" width="96px" height="15.75pt" data-latex="$$" />C. <img src="files/image5.png" width="34px" height="22px" data-latex="$$" />D. <img src="files/image6.png" width="32px" height="21px" data-latex="$$" /></p>
  7. <p>【答案】A</p>
  8. <p>【解析】</p>
  9. <p>B={x|x<sup>2</sup>﹣x>0}={x|x>1或x<0},</p>
  10. <p>由题意可知阴影部分对应的集合为∁<sub>U</sub>(A∩B)∩(A∪B),</p>
  11. <p>∴A∩B={x|1<x≤2},A∪B=R,</p>
  12. <p>即∁<sub>U</sub>(A∩B)={x|x≤1或x>2},</p>
  13. <p>∴∁<sub>U</sub>(A∩B)∩(A∪B)={x|x≤1或x>2},</p>
  14. <p>即(﹣∞,1]U(2,+∞)</p>
  15. <p>故选A</p>
  16. <p>2.下列各组函数中,<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />与<img src="files/image8.png" width="37px" height="27px" data-latex="$g\left( x \right)$" />相等的是( )</p>
  17. <p>A. <img src="files/image9.png" width="85px" height="27px" data-latex="$f\left( x \right)=2-x$" />,<img src="files/image10.png" width="90px" height="27px" data-latex="$g\left( x \right)=2-\left| x \right|$" />B. <img src="files/image11.png" width="81px" height="31px" data-latex="$f\left( x \right)=\sqrt{{{x}^{2}}}$" />,<img src="files/image12.png" width="91px" height="36px" data-latex="$g\left( x \right)={{\left( \sqrt[3]{x} \right)}^{3}}$" /></p>
  18. <p>C. <img src="files/image13.png" width="95px" height="44px" data-latex="$f\left( x \right)=\frac{{{x}^{2}}}{x}+2$" />,<img src="files/image14.png" width="84px" height="27px" data-latex="$g\left( x \right)=2+x$" />D. <img src="files/image15.png" width="95px" height="44px" data-latex="$f\left( x \right)=\frac{{{x}^{2}}-x}{x}$" />,<img src="files/image16.png" width="91px" height="44px" data-latex="$g\left( x \right)=\frac{{{x}^{2}}}{x}-1$" /></p>
  19. <p>【答案】D</p>
  20. <p>【解析】</p>
  21. <p>【分析】</p>
  22. <p>根据两个函数的定义域相同,解析式也相同,即可判断它们是相等函数.</p>
  23. <p>【详解】对于A,f(x)=2﹣x,与g(x)=2﹣|x|的解析式不同,不是相等函数;</p>
  24. <p>对于B,<img src="files/image17.png" width="111px" height="31px" data-latex="$f\left( x \right)=\sqrt{{{x}^{2}}}=\left| x \right|$" />,与g(x)<img src="files/image18.png" width="69px" height="36px" data-latex="$={{\left( \sqrt[3]{x} \right)}^{3}}=$" />x的解析式不同,不是相等函数;</p>
  25. <p>对于C,f(x)<img src="files/image19.png" width="47px" height="44px" data-latex="$=\frac{{{x}^{2}}}{x}+$" />2=x+2(x≠0),与g(x)=2+x(x∈R)的定义域不同,不是相等函数;</p>
  26. <p>对于D,f(x)<img src="files/image20.png" width="69px" height="44px" data-latex="$=\frac{{{x}^{2}}-x}{x}=$" />x﹣1(x≠0),与g(x)<img src="files/image21.png" width="47px" height="44px" data-latex="$=\frac{{{x}^{2}}}{x}-$" />1=x﹣1(x≠0)的定义域相同,对应关系也相同,是相等函数.</p>
  27. <p>故选:D.</p>
  28. <p><img src="files/image22.png" width="10px" height="18px" data-latex="$$" />点睛】本题考查了判断两个函数是否为相等函数的应用问题,是基础题.</p>
  29. <p>3.在定义域内既是奇函数又是减函数的是(  )</p>
  30. <p>A. <img src="files/image23.png" width="63px" height="41px" data-latex="$f(x)=\frac{1}{x}$" />B. <img src="files/image24.png" width="95px" height="41px" data-latex="$f(x)=-x+\frac{1}{x}$" /></p>
  31. <p>C. <img src="files/image25.png" width="92px" height="21px" data-latex="$f(x)=-x|x|$" />D. <img src="files/image26.png" width="171px" height="48px" data-latex="$f(x)=\left\{ \begin{array}{*{35}{l}} -x+1,x\in (0,+\infty ) \\ -x-1,x\in (-\infty ,0] \\\end{array} \right.$" /></p>
  32. <p>【答案】C</p>
  33. <p>【解析】</p>
  34. <p>【分析】</p>
  35. <p>根据奇偶性与单调性判断选择.</p>
  36. <p>【详解】<img src="files/image27.png" width="65px" height="41px" data-latex="$f\left( x \right)=\frac{1}{x}$" />在定义域<img src="files/image28.png" width="63px" height="21px" data-latex="$(-\infty ,0)\bigcup $" /> <img src="files/image29.png" width="49px" height="21px" data-latex="$(0,+\infty )$" />内是奇函数,但不是减函数,在区间<img src="files/image30.png" width="49px" height="21px" data-latex="$(-\infty ,0)$" />和<img src="files/image29.png" width="49px" height="21px" data-latex="$(0,+\infty )$" />上都是减函数</p>
  37. <p><img src="files/image31.png" width="97px" height="41px" data-latex="$f\left( x \right)=-x+\frac{1}{x}$" />在定义域<img src="files/image28.png" width="63px" height="21px" data-latex="$(-\infty ,0)\bigcup $" /> <img src="files/image29.png" width="49px" height="21px" data-latex="$(0,+\infty )$" />内是奇函数,但不是减函数,在区间<img src="files/image30.png" width="49px" height="21px" data-latex="$(-\infty ,0)$" />和<img src="files/image29.png" width="49px" height="21px" data-latex="$(0,+\infty )$" />上都是减函数</p>
  38. <p><img src="files/image32.png" width="217px" height="53px" data-latex="$f\left( x \right)=-x\left| x \right|=\left\{ \begin{matrix} -{{x}^{2}},x\in \left( 0,+\infty \right), \\ {{x}^{2}},x\in \left( -\infty ,0 \right] \\\end{matrix} \right.$" />在定义域<img src="files/image33.png" width="62px" height="21px" data-latex="$(-\infty ,+\infty )$" />内既是奇函数又是减函数</p>
  39. <p><img src="files/image34.png" width="180px" height="53px" data-latex="$f\left( x \right)=\left\{ \begin{matrix} -x+1,x\in \left( 0,+\infty \right), \\ -x-1,x\in \left( -\infty ,0 \right] \\\end{matrix} \right.$" />在定义域<img src="files/image33.png" width="62px" height="21px" data-latex="$(-\infty ,+\infty )$" />内不是奇函数(因为<img src="files/image35.png" width="93px" height="27px" data-latex="$f\left( 0 \right)=-1\ne 0$" />),</p>
  40. <p>综上选C.</p>
  41. <p>【点睛】本题考查函数奇偶性与单调性,考查基本分析判断能力,属基础题.</p>
  42. <p>4.已知<img src="files/image36.png" width="61px" height="24px" data-latex="$a=\sqrt{0.3}$" />,<img src="files/image37.png" width="111px" height="24px" data-latex="$b={{2}^{0.3}},c={{0.3}^{0.2}}$" />则<img src="files/image38.png" width="40px" height="21px" data-latex="$a,b,c$" />三者的大小关系是( )</p>
  43. <p>A. <img src="files/image39.png" width="60px" height="19px" data-latex="$b>c>a$" />B. <img src="files/image40.png" width="60px" height="19px" data-latex="$b>a>c$" />C. <img src="files/image41.png" width="53px" height="17px" data-latex="$a>b>c$" />D. <img src="files/image42.png" width="60px" height="19px" data-latex="$c>b>a$" /></p>
  44. <p>【答案】A</p>
  45. <p>【解析】</p>
  46. <p>因为<img src="files/image43.png" width="193px" height="27px" data-latex="$\text{a}\in \left( 0,1 \right),\text{b}>1,\text{c}\in \left( 0,1 \right),{{0.3}^{0.5}}$" />&lt;<img src="files/image44.png" width="36px" height="21px" data-latex="${{0.3}^{0.2}}$" />,所以<img src="files/image45.png" width="60px" height="19px" data-latex="$\text{a}<\text{c}<\text{b}$" />,选A.</p>
  47. <p>5.已知集合<img src="files/image46.png" width="235px" height="32px" data-latex="$A=\left\{ \left( x,y \right)\left| {{x}^{2}}+{{y}^{2}}\le 2,x\in Z,y\in Z \right. \right\}$" />,则<img src="files/image47.png" width="16px" height="18px" data-latex="$A$" />中元素的个数为( )</p>
  48. <p>A. <img src="files/image48.png" width="13px" height="17px" data-latex="$4$" />B. <img src="files/image49.png" width="12px" height="19px" data-latex="$5$" />C. <img src="files/image50.png" width="12px" height="19px" data-latex="$8$" />D. <img src="files/image51.png" width="12px" height="19px" data-latex="$9$" /></p>
  49. <p>【答案】D</p>
  50. <p>【解析】</p>
  51. <p>【分析】</p>
  52. <p>集合A的元素代表圆周及其内部的点,即可得到结论</p>
  53. <p>【详解】根据题意:A={(x,y)|x<sup>2</sup>+y<sup>2</sup>≤2,x,y∈Z}={(﹣1,﹣1),(﹣1,0),(﹣1,1),(0,﹣1),(0,0)(0,1),(1,﹣1),(1,0),(1,1)}共9个元素,是平面直角坐标系中9个点.</p>
  54. <p>故选:D.</p>
  55. <p>【点睛】本题考查集合的表示以及点与圆的位置关系,解题时需注意集合A的元素为两坐标均为整数的点,本题属于基础题.</p>
  56. <p>6.设定义在<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />上的函数<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />对任意实数<img src="files/image54.png" width="28px" height="17px" data-latex="$x,y$" />满足<img src="files/image55.png" width="152px" height="21px" data-latex="$f(x)+f(y)=f(x+y)$" />,且<img src="files/image56.png" width="60px" height="21px" data-latex="$f(2)=4$" />,则<img src="files/image57.png" width="89px" height="21px" data-latex="$f(0)+f(-2)$" />的值为( )</p>
  57. <p>A. -2B. <img src="files/image58.png" width="24px" height="21px" data-latex="$-\,4$" />C. 0D. 4</p>
  58. <p>【答案】B</p>
  59. <p>【解析】</p>
  60. <p>试题分析:令<img src="files/image59.png" width="62px" height="21px" data-latex="$x=y=0$" />,则有<img src="files/image60.png" width="125px" height="21px" data-latex="$f(0)+f(0)=f(0)$" />,故得<img src="files/image61.png" width="59px" height="21px" data-latex="$f(0)=0$" />,</p>
  61. <p>令<img src="files/image62.png" width="45px" height="19px" data-latex="$x=-2$" />,<img src="files/image63.png" width="39px" height="21px" data-latex="$y=2$" />,则有<img src="files/image64.png" width="159px" height="21px" data-latex="$f(-2)+f(2)=f(0)=0$" />,</p>
  62. <p>又<img src="files/image56.png" width="60px" height="21px" data-latex="$f(2)=4$" />,<img src="files/image65.png" width="89px" height="21px" data-latex="$\therefore f(-2)=-4$" /><img src="files/image66.png" width="135px" height="21px" data-latex="$\therefore f(0)+f(-2)=-4$" />故选<img src="files/image67.png" width="15px" height="16px" data-latex="$B$" />.</p>
  63. <p>考点:函数的值.</p>
  64. <p>7.已知集合<img src="files/image68.png" width="125px" height="32px" data-latex="$$" />,<img src="files/image69.png" width="145px" height="29px" data-latex="$$" />,若<img src="files/image70.png" width="67px" height="27px" data-latex="$A\bigcap \left( {{\complement }_{\text{R}}}B \right)$" />中恰好含有<img src="files/image71.png" width="13px" height="17px" data-latex="$2$" />个整数,则实数<img src="files/image72.png" width="13px" height="14px" data-latex="$a$" />的取值范围是( )</p>
  65. <p>A. <img src="files/image73.png" width="60px" height="19px" data-latex="$3<a<4$" />B. <img src="files/image74.png" width="60px" height="19px" data-latex="$3\le a<4$" />C. <img src="files/image75.png" width="60px" height="19px" data-latex="$3<a\le 4$" />D. <img src="files/image76.png" width="60px" height="19px" data-latex="$3\le a\le 4$" /></p>
  66. <p>【答案】B</p>
  67. <p>【解析】</p>
  68. <p>【分析】</p>
  69. <p>可根据题意得出∁<sub>R</sub>B={x|﹣4<x≤a},根据条件得出A∩(∁<sub>R</sub>B)={x|﹣4<x<﹣3或1<x≤a},从而可得出a的取值范围.</p>
  70. <p>【详解】根据题意,a>﹣4,则∁<sub>R</sub>B={x|﹣4<x≤a},</p>
  71. <p>又A={x|x<﹣3或x>1},A∩(∁<sub>R</sub>B)中恰好含有2个整数,</p>
  72. <p>∴A∩(∁<sub>R</sub>B)={x|﹣4<x<﹣3或1<x≤a},</p>
  73. <p>∴3≤a<4.</p>
  74. <p>故选:B.</p>
  75. <p>【点睛】本题考查描述法的定义,以及交集、补集的运算,注意数轴法的应用及端点值问题,是易错题</p>
  76. <p>8.已知函数<img src="files/image77.png" width="88px" height="42px" data-latex="$f\left( x \right)=\frac{x+2}{x-1}$" /><img src="files/image78.png" width="5px" height="9px" data-latex="$$" />记<img src="files/image79.png" width="245px" height="27px" data-latex="$f\left( 2 \right)+f\left( 3 \right)+f\left( 4 \right)+\cdots +f\left( 10 \right)=m,$" /><img src="files/image80.png" width="263px" height="45px" data-latex="$f\left( \frac{1}{2} \right)+f\left( \frac{1}{3} \right)+f\left( \frac{1}{4} \right)+\cdots +f\left( \frac{1}{10} \right)=n$" />,则<img src="files/image81.png" width="52px" height="16px" data-latex="$m+n=$" /></p>
  77. <p>A. <img src="files/image82.png" width="21px" height="19px" data-latex="$-9$" />B. 9C. <img src="files/image83.png" width="19px" height="19px" data-latex="$10$" />D. <img src="files/image84.png" width="30px" height="18px" data-latex="$-10$" /></p>
  78. <p>【答案】A</p>
  79. <p>【解析】</p>
  80. <p>【分析】</p>
  81. <p>推导出<img src="files/image85.png" width="117px" height="45px" data-latex="$f\left( x \right)+f\left( \frac{1}{x} \right)=-$" />1,再由f(2)+f(3)+f(4)+…+f(10)=m,<img src="files/image86.png" width="263px" height="45px" data-latex="$f\left( \frac{1}{2} \right)+f\left( \frac{1}{3} \right)+f\left( \frac{1}{4} \right)+\cdots +f\left( \frac{1}{10} \right)=n$" />,能求出m+n的值.</p>
  82. <p>【详解】解:∵函数<img src="files/image87.png" width="88px" height="41px" data-latex="$f\left( x \right)=\frac{x+2}{x-1}$" />,</p>
  83. <p>∴<img src="files/image88.png" width="217px" height="80px" data-latex="$f\left( x \right)+f\left( \frac{1}{x} \right)=\frac{x+2}{x-1}+\frac{\frac{1}{x}+2}{\frac{1}{x}-1}=-$" />1,</p>
  84. <p>∵f(2)+f(3)+f(4)+…+f(10)=m,<img src="files/image86.png" width="263px" height="45px" data-latex="$f\left( \frac{1}{2} \right)+f\left( \frac{1}{3} \right)+f\left( \frac{1}{4} \right)+\cdots +f\left( \frac{1}{10} \right)=n$" />,</p>
  85. <p>∴m+n=9×(﹣1)=﹣9.</p>
  86. <p>故选A.</p>
  87. <p>【点睛】本题考查函数值的求法,考查函数性质等基础知识,考查运算求解能力,是基础题.</p>
  88. <p>9.已知函数<img src="files/image89.png" width="133px" height="22px" data-latex="$f(x)=(x-a)(x-b)$" />(其中<img src="files/image90.png" width="33px" height="17px" data-latex="$a>b$" />),若<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />的图像如右图所示,则函数<img src="files/image91.png" width="88px" height="24px" data-latex="$g(x)={{a}^{x}}+b$" />的图像大致为( )</p>
  89. <p><img src="files/image92.png" width="168px" height="126px" /></p>
  90. <p>A. <img src="files/image93.png" width="118px" height="120px" />B. <img src="files/image94.png" width="118px" height="117px" />C. <img src="files/image95.png" width="116px" height="114px" />D. <img src="files/image96.png" width="111px" height="118px" /></p>
  91. <p>【答案】A</p>
  92. <p>【解析】</p>
  93. <p>【分析】</p>
  94. <p>根据<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />的图像,得到<img src="files/image97.png" width="57px" height="19px" data-latex="$0<a<1$" />,<img src="files/image98.png" width="44px" height="19px" data-latex="$b<-1$" />,进而可得出结果.</p>
  95. <p>【详解】由<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />的图像可知,<img src="files/image97.png" width="57px" height="19px" data-latex="$0<a<1$" />,<img src="files/image98.png" width="44px" height="19px" data-latex="$b<-1$" />,观察图像可知,答案选A.</p>
  96. <p>【点睛】本题主要考查二次函数图像,指数函数图像,熟记函数性质即可,属于常考题型.</p>
  97. <p>10.若不等式<img src="files/image99.png" width="103px" height="21px" data-latex="$a{{x}^{2}}+bx+4>0$" />的解集为<img src="files/image100.png" width="92px" height="29px" data-latex="$\left\{ x\left| -2<x<1 \right. \right\}$" />,则二次函数<img src="files/image101.png" width="105px" height="24px" data-latex="$y=b{{x}^{2}}+4x+a$" />在区间<img src="files/image102.png" width="36px" height="27px" data-latex="$\left[ 0,3 \right]$" />上的最大值、最小值分别为( ).</p>
  98. <p>A. <img src="files/image103.png" width="35px" height="21px" data-latex="$0,-8$" />B. <img src="files/image104.png" width="35px" height="21px" data-latex="$0,-4$" /></p>
  99. <p>C. <img src="files/image105.png" width="27px" height="21px" data-latex="$4,0$" />D. <img src="files/image106.png" width="25px" height="21px" data-latex="$8,0$" /></p>
  100. <p>【答案】A</p>
  101. <p>【解析】</p>
  102. <p>【详解】由题意知<img src="files/image107.png" width="37px" height="19px" data-latex="$a<0$" />且二次方程<img src="files/image108.png" width="103px" height="21px" data-latex="$a{{x}^{2}}+bx+4=0$" /><img src="files/image109.png" width="14px" height="19px" data-latex="$$" />两个根分别为<img src="files/image110.png" width="21px" height="17px" data-latex="$-2$" />和1.则有<img src="files/image111.png" width="59px" height="41px" data-latex="$-\frac{b}{a}=-1$" />,<img src="files/image112.png" width="49px" height="41px" data-latex="$\frac{4}{a}=-2$" />.故<img src="files/image113.png" width="47px" height="19px" data-latex="$a=-2$" />,<img src="files/image114.png" width="45px" height="19px" data-latex="$b=-2$" />.所以,二次函数<img src="files/image115.png" width="105px" height="24px" data-latex="$y=b{{x}^{2}}+4x+a$" />在区间<img src="files/image116.png" width="36px" height="27px" data-latex="$\left[ 0,3 \right]$" />上的最大值是0,最小值是<img src="files/image117.png" width="21px" height="19px" data-latex="$-8$" />. 选A.</p>
  103. <p>11.高斯是德国著名的数学家,近代数学奠基者之一,享有数学王子的美誉,他和阿基米德,牛顿并列为世界三大数学家,用其名字命名的“高斯函数”为:设<img src="files/image118.png" width="42px" height="19px" data-latex="$x\in R$" />,用<img src="files/image119.png" width="24px" height="27px" data-latex="$\left[ x \right]$" />表示不超过<img src="files/image120.png" width="13px" height="15px" data-latex="$x$" />的最大整数,则<img src="files/image121.png" width="48px" height="27px" data-latex="$y=\left[ x \right]$" />称为高斯函数,例如<img src="files/image122.png" width="67px" height="20px" data-latex="$$" />,<img src="files/image123.png" width="57px" height="27px" data-latex="$\left[ 2.1 \right]=2$" />.已知函数<img src="files/image124.png" width="116px" height="44px" data-latex="$f\left( x \right)=\frac{{{2}^{x}}}{{{2}^{x}}+1}-\frac{1}{2}$" />,则函数<img src="files/image125.png" width="79px" height="29px" data-latex="$y=\left[ f\left( x \right) \right]$" />的值域为( )</p>
  104. <p>A. <img src="files/image126.png" width="36px" height="27px" data-latex="$\left\{ 0,1 \right\}$" />B. <img src="files/image127.png" width="25px" height="27px" data-latex="$\left\{ 0 \right\}$" />C. <img src="files/image128.png" width="47px" height="27px" data-latex="$$" />D. <img src="files/image129.png" width="57px" height="27px" data-latex="$\left\{ -1,0,1 \right\}$" /></p>
  105. <p>【答案】C</p>
  106. <p>【解析】</p>
  107. <p>【分析】</p>
  108. <p><img src="files/image130.png" width="291px" height="44px" data-latex="$f\left( x \right)=\frac{{{2}^{x}}}{{{2}^{x}}+1}-\frac{1}{2}=\frac{{{2}^{x}}+1-1}{{{2}^{x}}+1}-\frac{1}{2}=\frac{1}{2}-\frac{1}{{{2}^{x}}+1}$" />,得函数f(x)为R上的增函数,所以f(x)∈(<img src="files/image131.png" width="27px" height="41px" data-latex="$-\frac{1}{2}$" />,<img src="files/image132.png" width="16px" height="41px" data-latex="$\frac{1}{2}$" />),进而可以得到y=[f(x)]的值域.</p>
  109. <p>【详解】依题意,<img src="files/image130.png" width="291px" height="44px" data-latex="$f\left( x \right)=\frac{{{2}^{x}}}{{{2}^{x}}+1}-\frac{1}{2}=\frac{{{2}^{x}}+1-1}{{{2}^{x}}+1}-\frac{1}{2}=\frac{1}{2}-\frac{1}{{{2}^{x}}+1}$" />,</p>
  110. <p>因为y=2<sup>x</sup>+1为R上的增函数,所以函数f(x)为R上的增函数,</p>
  111. <p>所以f(x)∈(<img src="files/image131.png" width="27px" height="41px" data-latex="$-\frac{1}{2}$" />,<img src="files/image132.png" width="16px" height="41px" data-latex="$\frac{1}{2}$" />),</p>
  112. <p>所以y=[f(x)]的值域为{﹣1,0},</p>
  113. <p>故选:C.</p>
  114. <p>【点睛】本题考查了新定义高斯函数,考查了函数的值域,函数的单调性,属于基础题.</p>
  115. <p>12.设集合<img src="files/image133.png" width="121px" height="27px" data-latex="$M=\left\{ 1,2,3,4,5,6 \right\}$" />,<img src="files/image134.png" width="80px" height="24px" data-latex="${{S}_{1}},{{S}_{2}},\cdots ,{{S}_{k}}$" />都是<img src="files/image135.png" width="22px" height="18px" data-latex="$M$" />的含两个元素的子集,且满足:对任意的<img src="files/image136.png" width="76px" height="27px" data-latex="${{S}_{i}}=\left\{ {{a}_{i}},{{b}_{i}} \right\}$" />,<img src="files/image137.png" width="83px" height="29px" data-latex="${{S}_{j}}=\left\{ {{a}_{j}},{{b}_{j}} \right\}$" />(<img src="files/image138.png" width="157px" height="27px" data-latex="$$" />),都有<img src="files/image139.png" width="193px" height="54px" data-latex="$\max \left\{ \frac{{{a}_{i}}}{{{b}_{i}}},\frac{{{b}_{i}}}{{{a}_{i}}} \right\}\ne \max \left\{ \frac{{{a}_{j}}}{{{b}_{j}}},\frac{{{b}_{j}}}{{{a}_{j}}} \right\}$" />(<img src="files/image140.png" width="71px" height="27px" data-latex="$\max \left\{ x,y \right\}$" />表示两个数<img src="files/image120.png" width="13px" height="15px" data-latex="$x$" />,<img src="files/image141.png" width="14px" height="18px" data-latex="$y$" />中的较大者),则<img src="files/image142.png" width="13px" height="19px" data-latex="$k$" />的最大值是( )</p>
  116. <p>A. <img src="files/image83.png" width="19px" height="19px" data-latex="$10$" />B. <img src="files/image143.png" width="17px" height="17px" data-latex="$11$" />C. <img src="files/image144.png" width="19px" height="17px" data-latex="$12$" />D. <img src="files/image145.png" width="19px" height="19px" data-latex="$13$" /></p>
  117. <p>【答案】B</p>
  118. <p>【解析】</p>
  119. <p>【分析】</p>
  120. <p>根据题意,首先分析出M的所有含2个元素的子集数目,进而对其特殊的子集分析排除,注意对min<img src="files/image146.png" width="72px" height="51px" data-latex="$$" />min<img src="files/image147.png" width="64px" height="53px" data-latex="$$" />(min{x,y}表示两个数x、y中的较小者)的把握,即可得答案.</p>
  121. <p>【详解】根据题意,对于M,含2个元素的子集有15个,</p>
  122. <p>但{1,2}、{2,4}、{3,6}只能取一个;</p>
  123. <p>{1,3}、{2,6}只能取一个;</p>
  124. <p>{2,3}、{4,6}只能取一个,</p>
  125. <p>故满足条件的两个元素的集合有11个;</p>
  126. <p>故选:B.</p>
  127. <p>【点睛】本题考查学生对集合及其子集、元素的把握、运用,注意对题意的分析.</p>
  128. <p>二、填空题(本大题共4个小题,每小题4分,共16分)</p>
  129. <p>13.已知集合<img src="files/image148.png" width="149px" height="29px" data-latex="$A=\left\{ 0,m,{{m}^{2}}-3m+2 \right\}$" />,且<img src="files/image149.png" width="38px" height="18px" data-latex="$2\in A$" />,求实数<img src="files/image150.png" width="17px" height="15px" data-latex="$m$" />的值______.</p>
  130. <p>【答案】3</p>
  131. <p>【解析】</p>
  132. <p>【分析】</p>
  133. <p>由题意结合集合元素的互异性分类讨论求解实数m的值即可.</p>
  134. <p>【详解】由题意分类讨论:</p>
  135. <p>若<img src="files/image151.png" width="42px" height="18px" data-latex="$m=2$" />,则<img src="files/image152.png" width="103px" height="21px" data-latex="${{m}^{2}}-3m+2=0$" />,不满足集合元素的互异性,舍去;</p>
  136. <p>若<img src="files/image153.png" width="103px" height="22px" data-latex="${{m}^{2}}-3m+2=2$" />,解得:<img src="files/image154.png" width="40px" height="19px" data-latex="$m=3$" />或<img src="files/image155.png" width="40px" height="19px" data-latex="$m=0$" />,</p>
  137. <p>其中<img src="files/image155.png" width="40px" height="19px" data-latex="$m=0$" />不满足集合元素的互异性,舍去,</p>
  138. <p>综上可得,<img src="files/image154.png" width="40px" height="19px" data-latex="$m=3$" />.</p>
  139. <p>【点睛】本题主要考查集合与元素的关系,集合元素的互异性等知识,意在考查学生的转化能力和计算求解能力.</p>
  140. <p>14.定义在<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />上的奇函数<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />满足:当<img src="files/image156.png" width="142px" height="24px" data-latex="$x\ge 0,f\left( x \right)={{x}^{2}}-2x+a$" />,则<img src="files/image157.png" width="59px" height="27px" data-latex="$f\left( -3 \right)=$" />__________.</p>
  141. <p>【答案】<img src="files/image158.png" width="21px" height="19px" data-latex="$-3$" /></p>
  142. <p>【解析】</p>
  143. <p><img src="files/image159.png" width="52px" height="27px" data-latex="$\because f\left( x \right)$" />为<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />上的奇函数,<img src="files/image160.png" width="331px" height="29px" data-latex="$\therefore f\left( 0 \right)=a=0,f\left( -3 \right)=-f\left( 3 \right)=-\left( {{3}^{2}}-2\times 3 \right)=-3$" />,</p>
  144. <p>故答案为<img src="files/image158.png" width="21px" height="19px" data-latex="$-3$" />.</p>
  145. <p>15.已知函数<img src="files/image161.png" width="157px" height="45px" data-latex="$f\left( x \right)=\frac{mx-1}{\sqrt{m{{x}^{2}}+4mx+3}}$" />的定义域为<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />,则实数<img src="files/image150.png" width="17px" height="15px" data-latex="$m$" />的取值范围是__________.</p>
  146. <p>【答案】.<img src="files/image162.png" width="44px" height="45px" data-latex="$\left[ 0,\frac{3}{4} \right)$" />.</p>
  147. <p>【解析】</p>
  148. <p>【分析】</p>
  149. <p>由题意可得,对任意实数x,mx<sup>2</sup>+4mx+3>0恒成立,然后分m=0和m≠0分类求解m的范围,取并集得答案.</p>
  150. <p>【详解】函数f(x)<img src="files/image163.png" width="121px" height="47px" data-latex="$=\frac{mx-1}{\sqrt{m{{x}^{2}}+4mx+3}}$" />的定义域为R,</p>
  151. <p>则对任意实数x,mx<sup>2</sup>+4mx+3>0恒成立,</p>
  152. <p>当m=0时,不等式3>0恒成立;</p>
  153. <p>当m≠0时,要使mx<sup>2</sup>+4mx+3>0恒成立,则<img src="files/image164.png" width="112px" height="48px" data-latex="$$" />,解得:0<img src="files/image165.png" width="57px" height="41px" data-latex="$$" />.</p>
  154. <p>综上,实数m的取值范围是[0,<img src="files/image166.png" width="16px" height="41px" data-latex="$\frac{3}{4}$" />).</p>
  155. <p>故答案为:[0,<img src="files/image166.png" width="16px" height="41px" data-latex="$\frac{3}{4}$" />).</p>
  156. <p>【点睛】本题考查函数的定义域及其求法,考查数学转化思想方法和分类讨论的数学思想方法,是中档题.</p>
  157. <p>16.关于函数<img src="files/image167.png" width="114px" height="52px" data-latex="$f\left( x \right)=\frac{\sqrt{{{x}^{2}}-{{x}^{4}}}}{\left| x-1 \right|-1}$" />的性质描述,正确的是__________.①<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />的定义域为<img src="files/image168.png" width="91px" height="27px" data-latex="$\left[ -1,0 \right)\bigcup \left( 0,1 \right]$" />;②<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />的值域为<img src="files/image169.png" width="39px" height="22px" data-latex="$\left( -1,1 \right)$" />;③<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />的图象关于原点对称;④<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />在定义域上是增函数.</p>
  158. <p>【答案】①②③</p>
  159. <p>【解析】</p>
  160. <p><img src="files/image22.png" width="10px" height="18px" data-latex="$$" />分析】</p>
  161. <p>由被开方式非负和分母不为0,解不等式可得f(x)的定义域,可判断①;化简f(x),讨论0<x≤1,﹣1≤x<0,分别求得f(x)的范围,求并集可得f(x)的值域,可判断②;由f(﹣1)=f(1)=0,f(x)不是增函数,可判断④;由奇偶性的定义得f(x)为奇函数,可判断③.</p>
  162. <p>【详解】①,由<img src="files/image170.png" width="89px" height="53px" data-latex="$\left\{ \begin{array}{*{35}{l}} {{x}^{2}}-{{x}^{4}}\ge 0 \\ \left| x-1 \right|-1\ne 0 \\\end{array} \right.$" />,解得﹣1≤x≤1且x≠0,</p>
  163. <p>可得函数<img src="files/image167.png" width="114px" height="52px" data-latex="$f\left( x \right)=\frac{\sqrt{{{x}^{2}}-{{x}^{4}}}}{\left| x-1 \right|-1}$" />的定义域为[﹣1,0)∪(0,1],故①正确;</p>
  164. <p>②,由①可得f(x)=<img src="files/image171.png" width="64px" height="47px" data-latex="$\frac{\sqrt{{{x}^{2}}-{{x}^{4}}}}{-x}$" />,即f(x)=﹣<img src="files/image172.png" width="76px" height="47px" data-latex="$\frac{|x|\sqrt{1-{{x}^{2}}}}{x}$" />,</p>
  165. <p>当0<x≤1可得f(x)=﹣<img src="files/image173.png" width="51px" height="27px" data-latex="$\sqrt{1-{{x}^{2}}}$" />∈(﹣1,0];当﹣1≤x<0可得f(x)=<img src="files/image173.png" width="51px" height="27px" data-latex="$\sqrt{1-{{x}^{2}}}$" />∈[0,1).</p>
  166. <p>可得f(x)的值域为(﹣1,1),故②正确;</p>
  167. <p>③,由f(x)=﹣<img src="files/image172.png" width="76px" height="47px" data-latex="$\frac{|x|\sqrt{1-{{x}^{2}}}}{x}$" />的定义域为[﹣1,0)∪(0,1],关于原点对称,</p>
  168. <p>f(﹣x)=<img src="files/image172.png" width="76px" height="47px" data-latex="$\frac{|x|\sqrt{1-{{x}^{2}}}}{x}$" />=﹣f(x),则f(x)为奇函数,即有f(x)的图象关于原点对称,故③正确.</p>
  169. <p>④,由f(﹣1)=f(1)=0,则f(x)在定义域上不是增函数,故④错误;</p>
  170. <p>故答案为:①②③</p>
  171. <p>【点睛】本题考查函数的性质和应用,主要是定义域和值域的求法、单调性的判断和图象的特征,考查定义法和分类讨论思想,以及化简运算能力和推理能力,属于中档题.</p>
  172. <p>三、解答题(本大题共6个小题,共48分)</p>
  173. <p>17.(1)计算:<img src="files/image174.png" width="196px" height="49px" data-latex="${{0.064}^{-\frac{1}{3}}}-{{\left( -\frac{1}{8} \right)}^{0}}+{{16}^{\frac{3}{4}}}+{{0.25}^{\frac{1}{2}}}$" />;</p>
  174. <p>(2)已知<img src="files/image175.png" width="69px" height="21px" data-latex="$x+{{x}^{-1}}=3$" />,求<img src="files/image176.png" width="54px" height="21px" data-latex="${{x}^{4}}-{{x}^{-4}}$" />的值.</p>
  175. <p>【答案】(1)10;(2) <img src="files/image177.png" width="41px" height="24px" data-latex="$\pm 3\sqrt{5}$" />.</p>
  176. <p>【解析】</p>
  177. <p>【分析】</p>
  178. <p>(1)利用指数运算性质即可得出.</p>
  179. <p>(2)由<img src="files/image175.png" width="69px" height="21px" data-latex="$x+{{x}^{-1}}=3$" />平方得<img src="files/image178.png" width="79px" height="21px" data-latex="${{x}^{2}}+{{x}^{-2}}=7$" />,进而得<img src="files/image179.png" width="87px" height="21px" data-latex="${{x}^{4}}+{{x}^{-4}}=47$" />,再利用<img src="files/image180.png" width="192px" height="24pt" data-latex="${{\left( {{x}^{2}}-{{x}^{-2}} \right)}^{2}}={{x}^{4}}-2+{{x}^{-4}}=45$" />即可得出.</p>
  180. <p>【详解】(1)原式<img src="files/image181.png" width="309px" height="44px" data-latex="$=\frac{1}{\sqrt[3]{0.064}}-1+\sqrt[4]{{{16}^{3}}}+\sqrt{0.25}=\frac{5}{2}-1+8+\frac{1}{2}=10$" /></p>
  181. <p>(2)由<img src="files/image175.png" width="69px" height="21px" data-latex="$x+{{x}^{-1}}=3$" /></p>
  182. <p>得<img src="files/image178.png" width="79px" height="21px" data-latex="${{x}^{2}}+{{x}^{-2}}=7$" /></p>
  183. <p>∴<img src="files/image179.png" width="87px" height="21px" data-latex="${{x}^{4}}+{{x}^{-4}}=47$" /></p>
  184. <p>∴<img src="files/image180.png" width="192px" height="24pt" data-latex="${{\left( {{x}^{2}}-{{x}^{-2}} \right)}^{2}}={{x}^{4}}-2+{{x}^{-4}}=45$" /></p>
  185. <p>即<img src="files/image182.png" width="105px" height="24px" data-latex="${{x}^{2}}-{{x}^{-2}}=\pm 3\sqrt{5}$" /></p>
  186. <p>【点睛】本题考查了指数运算性质、乘法公式及其变形,考查了推理能力与计算能力,属于基础题.</p>
  187. <p>18.已知函数<img src="files/image183.png" width="92px" height="41px" data-latex="$$" />.</p>
  188. <p>(1)判断<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />的奇偶性;</p>
  189. <p>(2)写出<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />的单调递增区间,并用定义证明.</p>
  190. <p>【答案】(1)奇函数;(2)<img src="files/image53.png" width="33px" height="20px" data-latex="$$" />在<img src="files/image184.png" width="64px" height="41px" data-latex="$(-\infty ,-\frac{1}{2})$" />上为增函数,证明见解析.</p>
  191. <p>【解析】</p>
  192. <p>试题分析:(1)由<img src="files/image185.png" width="101px" height="21px" />可得函数<img src="files/image186.png" width="36px" height="21px" />为奇函数;(2)证明如下.</p>
  193. <p>试题解析:(1)<img src="files/image186.png" width="36px" height="21px" />的定义域为<img src="files/image187.png" width="67px" height="27px" data-latex="$\left\{ x|x\ne 0 \right\}$" />.</p>
  194. <p>又<img src="files/image188.png" width="179px" height="41px" data-latex="$f(-x)=-(4x+\frac{1}{x})=-f(x)$" />,</p>
  195. <p>∴<img src="files/image186.png" width="36px" height="21px" />为奇函数.</p>
  196. <p>(2)<img src="files/image186.png" width="36px" height="21px" />的单调递增区间为<img src="files/image184.png" width="64px" height="41px" data-latex="$(-\infty ,-\frac{1}{2})$" />,<img src="files/image189.png" width="55px" height="41px" data-latex="$(\frac{1}{2},+\infty )$" />.</p>
  197. <p>证明:设<img src="files/image190.png" width="72px" height="41px" data-latex="$\frac{1}{2}<{{x}_{1}}<{{x}_{2}}$" />,<img src="files/image191.png" width="224px" height="45px" data-latex="$f({{x}_{1}})-f({{x}_{2}})=4{{x}_{1}}+\frac{1}{{{x}_{1}}}-4{{x}_{2}}-\frac{1}{{{x}_{2}}}$" /><img src="files/image192.png" width="136px" height="45px" data-latex="$=\frac{({{x}_{1}}-{{x}_{2}})(4{{x}_{1}}{{x}_{2}}-1)}{{{x}_{1}}{{x}_{2}}}$" />,</p>
  198. <p>∵<img src="files/image190.png" width="72px" height="41px" data-latex="$\frac{1}{2}<{{x}_{1}}<{{x}_{2}}$" />,∴<img src="files/image193.png" width="69px" height="24px" data-latex="${{x}_{1}}-{{x}_{2}}<0$" />,<img src="files/image194.png" width="81px" height="24px" data-latex="$4{{x}_{1}}{{x}_{2}}-1>0$" />,<img src="files/image195.png" width="55px" height="24px" data-latex="${{x}_{1}}{{x}_{2}}>0$" />,</p>
  199. <p>∴<img src="files/image196.png" width="115px" height="24px" data-latex="$f({{x}_{1}})-f({{x}_{2}})<0$" />,即<img src="files/image197.png" width="92px" height="24px" data-latex="$f({{x}_{1}})<f({{x}_{2}})$" />,</p>
  200. <p>∴<img src="files/image186.png" width="36px" height="21px" />在<img src="files/image189.png" width="55px" height="41px" data-latex="$(\frac{1}{2},+\infty )$" />上为增函数.</p>
  201. <p>同理,<img src="files/image186.png" width="36px" height="21px" />在<img src="files/image184.png" width="64px" height="41px" data-latex="$(-\infty ,-\frac{1}{2})$" />上为增函数.</p>
  202. <p>考点:函数的性质.</p>
  203. <p>19.已知全集<img src="files/image198.png" width="45px" height="19px" data-latex="$U=R$" />,集合<img src="files/image199.png" width="236px" height="29px" data-latex="$A=\left\{ \left. x \right|-3<x<2 \right\},B=\left\{ \left. x \right|1\le x\le 6 \right\}$" />,<img src="files/image200.png" width="161px" height="29px" data-latex="$C=\left\{ \left. x \right|a-1\le x\le 2a+1 \right\}$" />.</p>
  204. <p>(1)求<img src="files/image201.png" width="73px" height="27px" data-latex="$A\cap \left( {{C}_{U}}B \right)$" />;</p>
  205. <p>(2)若<img src="files/image202.png" width="73px" height="20px" data-latex="$C\subseteq A\cup B$" />,求实数<img src="files/image72.png" width="13px" height="14px" data-latex="$a$" />的取值范围.</p>
  206. <p>【答案】(1)<img src="files/image203.png" width="167px" height="29px" data-latex="$A\cap {{C}_{U}}B=\left\{ \left. x \right|-3<x<1 \right\}$" />;(2)<img src="files/image72.png" width="13px" height="14px" data-latex="$a$" />的取值范围是<img src="files/image204.png" width="125px" height="45px" data-latex="$\left( -\infty ,-2 \right)\cup \left( -2,\frac{5}{2} \right]$" /></p>
  207. <p>【解析】</p>
  208. <p>试题分析:(1)先求出<img src="files/image205.png" width="99px" height="29px" data-latex="${{C}_{U}}B=\left\{ \left. x \right| \right.x<1$" />或<img src="files/image206.png" width="43px" height="27px" data-latex="$\left. x>6 \right\}$" />,再根据交集的定义直接求出<img src="files/image207.png" width="73px" height="27px" data-latex="$A\cap \left( {{C}_{U}}B \right)$" />即可;(2)先求得<img src="files/image208.png" width="152px" height="29px" data-latex="$A\cup B=\left\{ \left. x \right|-3<x\le 6 \right\}$" />,在由<img src="files/image209.png" width="73px" height="20px" data-latex="$C\subseteq A\cup B$" />,考虑<img src="files/image210.png" width="45px" height="19px" data-latex="$C=\varnothing $" />后,根据子集的定义列不等式,即可求出<img src="files/image72.png" width="13px" height="14px" data-latex="$a$" />的取值范围.</p>
  209. <p>试题解析:(1)∵<img src="files/image205.png" width="99px" height="29px" data-latex="${{C}_{U}}B=\left\{ \left. x \right| \right.x<1$" />或<img src="files/image206.png" width="43px" height="27px" data-latex="$\left. x>6 \right\}$" />,<img src="files/image211.png" width="124px" height="29px" data-latex="$A=\left\{ \left. x \right|-3<x<2 \right\}$" />,</p>
  210. <p>∴<img src="files/image212.png" width="167px" height="29px" data-latex="$A\cap {{C}_{U}}B=\left\{ \left. x \right|-3<x<1 \right\}$" />.</p>
  211. <p>(2)<img src="files/image208.png" width="152px" height="29px" data-latex="$A\cup B=\left\{ \left. x \right|-3<x\le 6 \right\}$" />,</p>
  212. <p>①当<img src="files/image213.png" width="84px" height="19px" data-latex="$2a+1<a-1$" />即<img src="files/image214.png" width="45px" height="19px" data-latex="$a<-2$" />时,<img src="files/image215.png" width="103px" height="20px" data-latex="$C=\varnothing \subseteq A\cup B$" />;</p>
  213. <p>②当<img src="files/image216.png" width="84px" height="19px" data-latex="$2a+1\ge a-1$" />即<img src="files/image217.png" width="45px" height="19px" data-latex="$a\ge -2$" />时,要使<img src="files/image218.png" width="83px" height="20px" data-latex="$C=\subseteq A\cup B$" />,有<img src="files/image219.png" width="77px" height="48px" data-latex="$\left\{ \begin{matrix} a-1>-3, \\ 2a+1\le 6, \\\end{matrix} \right.$" /> ∴<img src="files/image220.png" width="59px" height="69px" data-latex="$\left\{ \begin{matrix} a>-2, \\ a\le \frac{5}{2}. \\\end{matrix} \right.$" /> </p>
  214. <p>又<img src="files/image217.png" width="45px" height="19px" data-latex="$a\ge -2$" />,∴<img src="files/image221.png" width="72px" height="41px" data-latex="$-2<a\le \frac{5}{2}$" />,∴<img src="files/image72.png" width="13px" height="14px" data-latex="$a$" />的取值范围是<img src="files/image204.png" width="125px" height="45px" data-latex="$\left( -\infty ,-2 \right)\cup \left( -2,\frac{5}{2} \right]$" />.</p>
  215. <p>20.某公司共有60位员工,为提高员工的业务技术水平,公司拟聘请专业培训机构进行培训.培训的总费用由两部分组成:一部分是给每位参加员工支付400元的培训材料费;另一部分是给培训机构缴纳的培训费.若参加培训的员工人数不超过30人,则每人收取培训费1000元;若参加培训的员工人数超过30人,则每超过1人,人均培训费减少20元.设公司参加培训的员工人数为x人,此次培训的总费用为y元.</p>
  216. <p>(1)求出y与x之间的函数关系式;</p>
  217. <p>(2)请你预算:公司此次培训的总费用最多需要多少元?</p>
  218. <p>【答案】(1) <img src="files/image222.png" width="256px" height="45px" data-latex="$y=\{\begin{array}{*{35}{l}} 1400x,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0\le x\le 30,x\in N \\ -20{{x}^{2}}+2000x,\,\,\,30<x\le 60,x\in N \\\end{array}$" /> (2)50000</p>
  219. <p>【解析】</p>
  220. <p>【分析】</p>
  221. <p>(1)依据参加培训的员工人数分段计算培训总费用.</p>
  222. <p>(2)依据(1)求出函数的最大值即可.</p>
  223. <p>【详解】(1)当<img src="files/image223.png" width="111px" height="21px" data-latex="$0\le x\le 30,x\in N$" />时,<img src="files/image224.png" width="171px" height="21px" data-latex="$y=400x+1000x=1400x$" />; </p>
  224. <p>当<img src="files/image225.png" width="119px" height="21px" data-latex="$30<x\le 60,x\in N$" />时,<img src="files/image226.png" width="211px" height="21px" data-latex="$y=400x+[1000-20(x-30)]\cdot x$" /></p>
  225. <p><img src="files/image227.png" width="112px" height="21px" data-latex="$=-20{{x}^{2}}+2000x$" />, </p>
  226. <p>故<img src="files/image228.png" width="259px" height="48px" data-latex="$y=\left\{ \begin{array}{*{35}{l}} 1400x,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0\le x\le 30,x\in N \\ -20{{x}^{2}}+2000x,\,\,\,30<x\le 60,x\in N \\\end{array} \right.$" /> </p>
  227. <p>(2)当<img src="files/image223.png" width="111px" height="21px" data-latex="$0\le x\le 30,x\in N$" />时,</p>
  228. <p><img src="files/image229.png" width="144px" height="21px" data-latex="$y\le 1400\times 30=42000$" />元,此时x=30;</p>
  229. <p>当<img src="files/image225.png" width="119px" height="21px" data-latex="$30<x\le 60,x\in N$" />时,</p>
  230. <p><img src="files/image230.png" width="219px" height="24px" data-latex="$y\le -20\times {{50}^{2}}+2000\times 50=50000$" />元,此时<img src="files/image231.png" width="45px" height="19px" data-latex="$x=50$" />. </p>
  231. <p>综上所述,公司此次培训的总费用最多需要<img src="files/image232.png" width="44px" height="19px" data-latex="$50000$" />元.</p>
  232. <p>【点睛】本题考察函数的应用,要求依据实际问题构建分段函数的数学模型并依据数学模型求实际问题的最大值,注意建模时理顺各数据间的关系.</p>
  233. <p>21.已知指数函数<img src="files/image233.png" width="62px" height="27px" data-latex="$y=g\left( x \right)$" />满足<img src="files/image234.png" width="68px" height="27px" data-latex="$g\left( 3 \right)=27$" />,定义域为<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />的函数<img src="files/image235.png" width="123px" height="49px" data-latex="$f\left( x \right)=\frac{n-g\left( x \right)}{m+3g\left( x \right)}$" />是奇函数.</p>
  234. <p>(1)求函数<img src="files/image233.png" width="62px" height="27px" data-latex="$y=g\left( x \right)$" />,<img src="files/image236.png" width="64px" height="27px" data-latex="$y=f\left( x \right)$" />的解析式;</p>
  235. <p>(2)若对任意的<img src="files/image237.png" width="49px" height="23px" data-latex="$t\in \left( 1,4 \right)$" />,不等式<img src="files/image238.png" width="156px" height="27px" data-latex="$f\left( 2t-3 \right)+f\left( t-k \right)>0$" />恒成立,求实数<img src="files/image142.png" width="13px" height="19px" data-latex="$k$" />的取值范围.</p>
  236. <p>【答案】(1) <img src="files/image239.png" width="101px" height="44px" data-latex="$f\left( x \right)=\frac{1-{{3}^{x}}}{3+{{3}^{x+1}}}$" />;(2) <img src="files/image240.png" width="49px" height="27px" data-latex="$\left[ 9,+\infty \right)$" />.</p>
  237. <p>【解析】</p>
  238. <p>【分析】</p>
  239. <p>(1)设g(x)=a<sup>x</sup>(a>0且a≠1),根据g(3)=27,得g(x),利用定义域为R的函数f(x)<img src="files/image241.png" width="85px" height="49px" data-latex="$=\frac{n-g\left( x \right)}{m+3g\left( x \right)}$" />是奇函数即可解出;</p>
  240. <p>(2)对任意的t∈R不等式<img src="files/image238.png" width="156px" height="27px" data-latex="$f\left( 2t-3 \right)+f\left( t-k \right)>0$" />恒成立,则<img src="files/image242.png" width="212px" height="27px" data-latex="$f\left( 2t-3 \right)>-f\left( t-k \right)=f\left( k-t \right)$" />化为<img src="files/image243.png" width="62px" height="19px" data-latex="$3t-3<k$" />在<img src="files/image237.png" width="49px" height="23px" data-latex="$t\in \left( 1,4 \right)$" />上恒成立,求一次函数最值即可得出</p>
  241. <p>【详解】(1)设<img src="files/image244.png" width="158px" height="27px" data-latex="$$" />,则<img src="files/image245.png" width="52px" height="21px" data-latex="${{a}^{3}}=27$" /></p>
  242. <p>∴<img src="files/image246.png" width="36px" height="19px" data-latex="$a=3$" /></p>
  243. <p>∴<img src="files/image247.png" width="65px" height="27px" data-latex="$g\left( x \right)={{3}^{x}}$" /></p>
  244. <p>∴<img src="files/image248.png" width="107px" height="44px" data-latex="$f\left( x \right)=\frac{n-{{3}^{x}}}{m+{{3}^{x+1}}}$" /></p>
  245. <p>∵<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />是奇函数</p>
  246. <p>∴<img src="files/image249.png" width="61px" height="27px" data-latex="$f\left( 0 \right)=0$" />,即<img src="files/image250.png" width="116px" height="41px" data-latex="$\frac{n-1}{3+m}=0\Rightarrow n=1$" /></p>
  247. <p>∴<img src="files/image251.png" width="107px" height="44px" data-latex="$f\left( x \right)=\frac{1-{{3}^{x}}}{{{3}^{x+1}}+m}$" /></p>
  248. <p>又<img src="files/image252.png" width="101px" height="27px" data-latex="$f\left( -1 \right)=-f\left( 1 \right)$" /></p>
  249. <p>∴<img src="files/image253.png" width="158px" height="60px" data-latex="$\frac{1-\frac{1}{3}}{m+1}=-\frac{1-3}{9+m}\Rightarrow m=3$" /></p>
  250. <p>∴<img src="files/image239.png" width="101px" height="44px" data-latex="$f\left( x \right)=\frac{1-{{3}^{x}}}{3+{{3}^{x+1}}}$" />,经检验<img src="files/image254.png" width="97px" height="27px" data-latex="$f\left( -x \right)=f\left( x \right)$" />成立</p>
  251. <p>(2)由(1)知<img src="files/image255.png" width="285px" height="44px" data-latex="$f\left( x \right)=\frac{1-{{3}^{x}}}{3+{{3}^{x+1}}}=-\frac{1}{3}\cdot \frac{{{3}^{x}}-1}{{{3}^{x}}+1}=-\frac{1}{3}+\frac{2}{3}\cdot \frac{1}{{{3}^{x}}+1}$" /></p>
  252. <p>∴<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />在<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />上为减函数</p>
  253. <p>又∵<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />是奇函数</p>
  254. <p><img src="files/image238.png" width="156px" height="27px" data-latex="$f\left( 2t-3 \right)+f\left( t-k \right)>0$" /></p>
  255. <p>∴<img src="files/image242.png" width="212px" height="27px" data-latex="$f\left( 2t-3 \right)>-f\left( t-k \right)=f\left( k-t \right)$" /></p>
  256. <p>∵<img src="files/image7.png" width="39px" height="27px" data-latex="$f\left( x \right)$" />是减函数,由上式得:<img src="files/image256.png" width="83px" height="19px" data-latex="$2t-3<k-t$" /></p>
  257. <p>即对任意的<img src="files/image237.png" width="49px" height="23px" data-latex="$t\in \left( 1,4 \right)$" />,有<img src="files/image243.png" width="62px" height="19px" data-latex="$3t-3<k$" />恒成立</p>
  258. <p>令<img src="files/image257.png" width="81px" height="27px" data-latex="$h\left( t \right)=3t-3$" />,<img src="files/image237.png" width="49px" height="23px" data-latex="$t\in \left( 1,4 \right)$" />,易知<img src="files/image258.png" width="32px" height="27px" data-latex="$h\left( t \right)$" />在<img src="files/image237.png" width="49px" height="23px" data-latex="$t\in \left( 1,4 \right)$" />上递增</p>
  259. <p>所以<img src="files/image259.png" width="163px" height="27px" data-latex="$h\left( t \right)<h(3)=3\times 4-3=9$" /></p>
  260. <p>∴<img src="files/image260.png" width="37px" height="19px" data-latex="$k\ge 9$" />,即实数<img src="files/image142.png" width="13px" height="19px" data-latex="$k$" />的取值范围为<img src="files/image240.png" width="49px" height="27px" data-latex="$\left[ 9,+\infty \right)$" /></p>
  261. <p><img src="files/image22.png" width="10px" height="18px" data-latex="$$" />点睛】本题综合考查了指数函数的定义及其性质、函数的奇偶性、单调性、恒成立问题的等价转化、一次函数的单调性等基础知识与基本技能方法,属于难题</p>
  262. <p>22.定义对于函数<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />, 若在定义域内存在实数<img src="files/image120.png" width="13px" height="15px" data-latex="$x$" />, 满足<img src="files/image261.png" width="107px" height="27px" data-latex="$f\left( -x \right)=-f\left( x \right)$" />,则称<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />为“局部奇函数”.</p>
  263. <p>(1)已知二次函数<img src="files/image262.png" width="225px" height="27px" data-latex="$f\left( x \right)=a{{x}^{2}}+2x-4a\left( a\in R,a\ne 0 \right)$" />,试判断<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />是否为定义域<img src="files/image52.png" width="16px" height="18px" data-latex="$R$" />上的“局部奇函数”若是,求出满足<img src="files/image261.png" width="107px" height="27px" data-latex="$f\left( -x \right)=-f\left( x \right)$" />的<img src="files/image120.png" width="13px" height="15px" data-latex="$x$" />的值; 若不是, 请说明理由;</p>
  264. <p>(2)若<img src="files/image263.png" width="96px" height="20.25pt" />是定义在区间<img src="files/image264.png" width="41px" height="27px" data-latex="$\left[ -1,1 \right]$" />上的“局部奇函数”,求实数<img src="files/image150.png" width="17px" height="15px" data-latex="$m$" />的取值范围.</p>
  265. <p>【答案】(1)<img src="files/image265.png" width="45px" height="19px" data-latex="$x=\pm 2$" />,<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />为“局部奇函数;(2)<img src="files/image266.png" width="91px" height="45px" data-latex="$m\in \left[ -\frac{5}{4},-1 \right]$" />.</p>
  266. <p>【解析】</p>
  267. <p>试题分析:(1)若<img src="files/image267.png" width="35px" height="22px" />为“局部奇函数”,则根据定义验证条件是否成立即可;(2)利用局部奇函数的定义,求出使方程<img src="files/image268.png" width="100px" height="22px" />有解的实数<img src="files/image269.png" width="17px" height="15px" />的取值范围,可得答案.</p>
  268. <p>试题解析:(1) 当<img src="files/image270.png" width="187px" height="27px" data-latex="$f\left( x \right)=a{{x}^{2}}+2x-4a\left( a\in R \right)$" />,方程<img src="files/image271.png" width="120px" height="27px" data-latex="$f\left( x \right)+f\left( -x \right)=0$" />即<img src="files/image272.png" width="97px" height="29px" data-latex="$2a\left( {{x}^{2}}-4 \right)=0$" />,有解<img src="files/image265.png" width="45px" height="19px" data-latex="$x=\pm 2$" />,所以<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />为 “局部奇函数”.</p>
  269. <p>(2)当<img src="files/image263.png" width="96px" height="20.25pt" />时,<img src="files/image271.png" width="120px" height="27px" data-latex="$f\left( x \right)+f\left( -x \right)=0$" />可化为<img src="files/image273.png" width="113px" height="21px" data-latex="${{2}^{x}}+{{2}^{-x}}+2m=0$" />,因为<img src="files/image7.png" width="39px" height="26px" data-latex="$f\left( x \right)$" />的定义域为<img src="files/image264.png" width="41px" height="27px" data-latex="$\left[ -1,1 \right]$" />,所以方程<img src="files/image273.png" width="113px" height="21px" data-latex="${{2}^{x}}+{{2}^{-x}}+2m=0$" />在<img src="files/image264.png" width="41px" height="27px" data-latex="$\left[ -1,1 \right]$" />上有解.令<img src="files/image274.png" width="96px" height="33.75pt" />,则<img src="files/image275.png" width="76px" height="41px" data-latex="$-2m=t+\frac{1}{t}$" />,设<img src="files/image276.png" width="77px" height="41px" data-latex="$g\left( t \right)=t+\frac{1}{t}$" />,则</p>
  270. <p><img src="files/image276.png" width="77px" height="41px" data-latex="$g\left( t \right)=t+\frac{1}{t}$" />在<img src="files/image277.png" width="55px" height="27px" data-latex="$t\in \left( 0,1 \right]$" />上为减函数,在<img src="files/image278.png" width="68px" height="27px" data-latex="$t\in \left[ 1,+\infty \right)$" />上为增函数,(要证明),所以当<img src="files/image279.png" width="65px" height="45px" data-latex="$t\in \left[ \frac{1}{2},2 \right]$" />时,<img src="files/image280.png" width="88px" height="45px" data-latex="$g\left( t \right)\in \left[ 2,\frac{5}{2} \right]$" />,所以<img src="files/image281.png" width="88px" height="45px" data-latex="$-2m\in \left[ 2,\frac{5}{2} \right]$" />,即<img src="files/image266.png" width="91px" height="45px" data-latex="$m\in \left[ -\frac{5}{4},-1 \right]$" />.</p>
  271. <p>考点:二次函数的性质.</p>
  272. <p>【方法点睛】本题主要考查新定义的应用,利用新定义,建立方程关系,然后利用函数性质进行求解是解决本题的关键,考查学生的运算能力.在该种题型中主要考查两个方面一是新定义判定的考查;二是新定义性质的考查,理解局部奇函数的定义,对<img src="files/image270.png" width="187px" height="27px" data-latex="$f\left( x \right)=a{{x}^{2}}+2x-4a\left( a\in R \right)$" />按定义验证即可;在(2)中考查了局部奇函数的性质,将题意转化为<img src="files/image273.png" width="113px" height="21px" data-latex="${{2}^{x}}+{{2}^{-x}}+2m=0$" />在<img src="files/image264.png" width="41px" height="27px" data-latex="$\left[ -1,1 \right]$" />上有解的问题.</p>
  273. <p> </p>
  274. <p> </p>
  275. <p> </p>
  276. </body></html>