299 lines
3.2 KiB
Plaintext
299 lines
3.2 KiB
Plaintext
ans
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024622
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$[2,3]$
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024623
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$[2,+\infty)$
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024624
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$[0,+\infty)$
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024625
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$x=a$或$x=b$
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024626
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$6$
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024627
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$[2,+\infty)$
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024628
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$\mathbf{R}$
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024629
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$0$
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024630
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$(-\infty,1)$
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024631
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$B\subset A$
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024632
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A
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024633
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A
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024634
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D
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024635
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D
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024636
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$10$
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024637
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(1) $x=2$, $y=-1$; (2) $\overline{A \cap B}=\{-3,-2,0,1,2\}$, $\overline{A \cup B}=\{-3,0,1\}$
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024638
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(1) $(1,2]\cup [3,+\infty)$
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024639
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(1) $(-\dfrac{1}{3},1)$; (2) $(-\infty,-\dfrac{1}{2}]\cup [\dfrac{3}{2},+\infty)$
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024640
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(1) $(-3,3]$; (2) $[3,+\infty)$
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024641
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$<$
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024642
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$(-\dfrac{1}{7},\dfrac{1}{5})$
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024643
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必要非充分
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024644
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$[3,+\infty)$
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024645
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$[-\dfrac{3}{2},3)$
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024646
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$\{11,12,14,15\}$
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024647
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$-4$
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024648
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$-1$
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024649
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$[7,8]$
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024650
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\textcircled{3}\textcircled{5}
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024651
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D
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024652
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C
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024653
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D
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024654
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A
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024655
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$[-\dfrac{1}{2}, 0)\cup (0,+\infty)$
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024656
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$[\dfrac{1}{2},2]$
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024657
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恒成立, 证明略
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024658
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高为$88\text{cm}$, 宽为$55\text{cm}$
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024659
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(1) $(\infty,-2)\cup (2,+\infty)$; (2) 证明略
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024660
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$\dfrac{8}{5}$
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024661
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$-9a$
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024662
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$2+\dfrac{3\sqrt{2}}{2}$
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024663
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$12$
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024664
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$\dfrac{5a-3b+3}{2}$
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024665
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$4$
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024666
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$10$
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024667
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$7\sqrt{2}$
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024668
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$0$或$1$
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024669
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$1$
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024670
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B
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024671
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D
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024672
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B
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024673
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D
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024674
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(1) $8$; (2) $3$; (3) $21\sqrt{5}$
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024675
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$a=6$, $b=8$, $c=10$
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024676
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$-4$
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024677
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最大值为$0$, 最小值为$-1$
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024678
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$0$
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024679
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$y=x^3$
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024680
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$(-\infty,0)\cup (\dfrac{1}{3},+\infty)$
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024681
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$(0,+\infty)$
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024682
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$\dfrac{1}{2}$
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024683
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$1$
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024684
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$(-4,-1)\cup (4,+\infty)$
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024685
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$(-\infty,-1]\cup [3,+\infty)$
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024686
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$(0,1)$
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024687
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$(-1,-\dfrac{1}{2}$
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024688
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$(0,\dfrac{1}{4}]$
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024689
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C
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024690
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C
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024691
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D
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024692
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A
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024693
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$1,3,5$或$7$
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024694
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$(-\infty,-1)\cup (0,+\infty)$
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024695
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(1) $3$年; (2) 按第二种方式能获得更多的利息, 利息差约为$1139.11$元
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024696
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$(-\infty,-8]$
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024697
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最大值为$2$, 最小值为$0$
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024698
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$\dfrac{1-x}{1+x}$
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024699
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偶
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024700
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$1$
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024701
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$x^2-2$
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024702
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$[-1,+\infty)$
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024703
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$2\sqrt{2}$
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024704
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$[1,4]$
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024705
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$[-4,-\dfrac{3}{2}]$
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024706
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$\dfrac{27}{2}$
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024707
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$[\dfrac{1}{2},1)\cup [3,+\infty)$
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024708
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A
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024709
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D
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024710
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B
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024711
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C
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024712
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(1) $g(m)=-(m-\dfrac{1}{2})^2-\dfrac{3}{4}$; (2) 最大值为$-\dfrac{3}{4}$, 最小值为$-3$
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024713
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(1) 在$(0,\sqrt{3}]$上严格减, 在$[\sqrt{3},+\infty)$上严格增, 大致图像如下: \begin{center}
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\begin{tikzpicture}[>=latex, scale = 0.3]
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\draw [->] (0,0) -- (8,0) node [below] {$x$};
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\draw [->] (0,0) -- (0,{8+3/8}) node [left] {$y$};
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\draw (0,0) node [below left] {$O$};
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\draw [domain = {3/8}:8, samples = 100] plot (\x,{\x+3/\x});
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\end{tikzpicture}
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\end{center}
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(2) 当$0<a\le 4$时, 最小值为$2\sqrt{a}$, 当$a>4$时, 最小值为$2+\dfrac{a}{2}$
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024714
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(1) $g(x)=-x^2+2x$; (2) $(-\infty,0]$
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024715
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(1) $f(x)=\begin{cases}\dfrac{1}{x^2+1}, & x>0, \\ 0, & x=0, \\ -\dfrac{1}{x^2+1}, & x<0;\end{cases}$ (2) $(-1,1)$
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024716
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(1) $p(t)=\begin{cases}-2t^2+40t+200, & 2\le t<10, \\ 400, & 10\le t\le 20,\end{cases}$ 发车间隔为$8$分钟时, 电车的载客量为$392$人; (2) 发车间隔为$5$分钟时, 该线路每分钟的收益最大
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024717
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(1) 都是``均分函数'', 理由略; (2) $[\dfrac{1}{9},+\infty)$; (3) $[\dfrac{1}{3},\dfrac{7}{3}]$
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