ans

012613
$\{2,4\}$

012614
$(1,2)$

012615
$\dfrac{\sqrt{2}}2$

012616
$3$

012617
$3$

012618
\textcircled{1}\textcircled{4}

012619
$180$

012620
$4$

012621
$\dfrac 52$

012622
$\dfrac\pi 4$

012623
$\dfrac{8\sqrt{2}\pi}3$

012624
$\dfrac{8\sqrt{3}}3$

012625
A

012626
C

012627
D

012628
C

012629
(1) $b_n=3^{n-1}$; (2) $-8$

012630
(1) $\dfrac \pi 4$; (2) $1$

012631
(1) 证明略; (2) 证明略; (3) $\dfrac\pi 4$

012632
(1) $\sqrt{2}$; (2) $y=x+1$; (3) 过定点$(-3,0)$和$(1,0)$

012633
(1) $y=x-1$; (2) 单调减区间为$(\dfrac 12 1)$; 极小值为$-2$; (3) 证明略

012571
$\{1\}$

012572
$-1$

012573
$\dfrac\pi 6$

012574
$2$

012575
$16\pi$

012576
$2800$, $31$

012577
$2$

012578
$(-\infty,1)\cup (1,3]$

012579
$5$

012580
$[\dfrac 32,2]$

012581
$(\dfrac 72,0,\dfrac 72)$

012582
$\dfrac{\sqrt{3}}{20}v$

012583
A

012584
D

012585
C

012586
C

012587
(1) 证明略; (2) $\dfrac{3\sqrt{22}}{11}$

012588
(1) $\dfrac 12$; (2) $a_n=\dfrac{18}{2n+1}$

012589
(1) 例如: 非通勤时段的车辆使用情况; 油价和电价的变化; 工作单位能否提供免费充电; 电动车的国家减免政策的变化; 车辆的外观、内饰与品牌效应; 车牌费用等; (2) 解答略


012590
(1) $\dfrac{x^2}4+\dfrac{y^2}3=1$($y\le 0$); (2) $P(-\dfrac 32,\dfrac{\sqrt{3}}2)$, $Q(\dfrac 32, \dfrac{\sqrt{3}}2)$; (3) $[\sqrt{3}-1,\sqrt{2}+1]$

012591
(1) 导数为$y'=\dfrac{1-\ln x}{x^2}$, 单调性证明略; (2) 判断$89^{99}>99^{89}$, 证明略, 推广可以是:``对于实数$a,b$, 若$\mathrm{e}<a<b$, 则$a^b>b^a$; (3) 证明略


010965
$[0,2]$

010966
$(-\infty,0)$

030023
$\dfrac{3n^2-5n}2$

010968
$\dfrac{8\pi}3$

010969
$2(x+2)-(y-1)=0$

010970
$\dfrac 32$

030025
$[0,\dfrac 34]$

010972
$25$

030024
$\dfrac 23(\dfrac 1{4^n}-1)$

010974
$[1,+\infty)$

010975
$\sqrt{3}$

010976
$3-\sqrt{3}$

010977
B

002745
C

010979
C

010980
B

010981
(1) $\dfrac 23$; (2) $\arctan {2\sqrt{5}}5$

010982
(1) $\log_2 3$; (2) $a=2b\ne 0$

010983
(1) $\sqrt{7}$千米; (2) 有$\dfrac{8-\sqrt{15}}7$小时, 两人不能通话

010984
(1) $y^2=4\sqrt{5} x$或$y^2=-4\sqrt{5} x$; (2) $M$的坐标为$(0,0)$或$(-\dfrac{4\sqrt{5}}5,0)$; (3) 证明略

010985
(1) $\{-6,-3,-2,-1,0,1,2,3,4\}$; (2) 证明略; (3) 元素个数为$\dfrac 12 n(n+1)$; 元素之和为$\dfrac{n+1}2(3^{n+1}-3)$