Just answer directly. If you get stuck, tap "Give me a hint" or "Help me understand". A wrong answer won't instantly reveal the solution.
Question 1 · Free response · 中档
(5分)已知集合 $\cdot \mathsf { A } \mathrm { = } \{ \mathbf { x } | \mathbf { x } { < } 1 \}$ $\mathsf { B } = \left\{ \mathsf { x } \big | 3 ^ { \mathsf { x } } < 1 \right\}$ ,则( )A $\mathsf { A } \cap \mathsf { B } = \{ \mathsf { x } | \mathsf { x } < 0 \}$ B $A \cup \mathsf { B } { = } \mathsf { R }$ C $\mathsf { A U B } { = } \{ { \mathsf { x } } | { \mathsf { x } } { > } 1 \}$ D $\textsf { Abigcap B } = \emptyset$
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 2 · Free response · 中档
(5分)如图,正方形ABCD内的图形来自中国古代的太极图.正方形内切圆中的黑色部分和白色部分关于正方形的中心成中心对称.在正方形内随机取一点,则此点取自黑色部分的概率是( )
A $\frac { 1 } { 4 }$ B $\frac { \pi } { 8 }$ C $\frac { 1 } { 2 }$ D $\frac { \pi } { 4 }$
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 3 · Single choice · 中档
(5分)设有下面四个命题
$\mathsf { p } _ { 1 } \mathsf { : }$ 若复数z满足 $\frac { 1 } { z } E R$ ,则 $z { \in } { \mathsf { R } }$ ;
${ \mathsf { p } } _ { 2 } \mathbf { : }$ 若复数z满足 $z ^ { 2 } \in \mathsf { R }$ ,则 $z { \in } { \mathsf { R } }$ ;
${ \mathsf p } _ { 3 } \colon$ 若复数 $\cdot \sf { z } _ { 1 } , \sf { z } _ { 2 }$ 满足 $z _ { 1 } z _ { 2 } \in \mathsf { R }$ ,则 $\scriptstyle \mathsf { z } _ { 1 } = \overline { { \mathsf { z } _ { 2 } } } ;$
$\mathsf { p } _ { 4 } \mathsf { : }$ 若复数 $. z \in { \mathsf { R } }$ ,则 $\overline { { z } } \in R$
其中的真命题为( )
A. p<sub>1</sub>,p<sub>3</sub> B. p<sub>1</sub>,p<sub>4</sub> C. p<sub>2</sub>,p<sub>3</sub> D. p<sub>2</sub>,p<sub>4</sub>
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 4 · Single choice · 中档
(5分)记 $\displaystyle \lvert S _ { \mathrm { n } }$ 为等差数列 $\{ \mathsf { a } _ { \mathsf { n } } \}$ 的前n项和.若 $a _ { 4 } + 2 _ { 5 } = 2 4 , S _ { 6 } = 4 8$ ,则 $\{ \mathsf { a } _ { \mathsf { n } } \}$ 的公差 为( )
A. 1 B. 2 C. 4 D. 8
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 5 · Single choice · 中档
(5分)函数f(x)在 $( \mathrm { ~ - ~ } \infty , \mathrm { ~ \mp \infty ~ } )$ 单调递减,且为奇函数.若f(1)=﹣1,则满足﹣1≤f(x﹣2)≤1的x的取值范围是( )
A. [﹣2,2] B. [﹣1,1] C. [0,4] D. [1,3]
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 6 · Single choice · 中档
(5分) $( 1 + \frac { 1 } { ~ \mathbf { x } ^ { 2 } } ) \quad ( 1 + \mathbf { x } )$ <sup>6</sup>展开式中x<sup>2</sup>的系数为( )
A. 15 B. 20 C. 30 D. 35
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 7 · Single choice · 中档
(5分)某多面体的三视图如图所示,其中正视图和左视图都由正方形和等腰直角三角形组成,正方形的边长为2,俯视图为等腰直角三角形,该多面体的各个面中有若干个是梯形,这些梯形的面积之和为( )
A. 10 B. 12 C. 14 D. 16
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 8 · Single choice · 中档
(5分)如图程序框图是为了求出满足 $3 ^ { \mathsf { n } } - 2 ^ { \mathsf { n } } { > } 1 0 0 0$ 的最小偶数n,那么在
两个空白框中,可以分别填入( )
A. $_ { \mathsf { A } > 1 0 0 0 }$ 和n=n+1 B. A>1000和$n=n+2$ C. $\mathsf { A } { \leq } 1 0 0 0 $ 和 $n = n + 1$ D. $\mathsf { A } { \leq } 1 0 0 0$ 和 $n = n + 2$
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 9 · Single choice · 中档
(5分)已知曲线 $\mathsf C _ { 1 }$ $y = \cos x , C _ { 2 } : y = \sin ( 2 x + \frac { 2 \pi } { 3 } )$ ,则下面结论正确的是( )
A. 把 $\mathsf { C } _ { 1 }$ 上各点的横坐标伸长到原来的2倍,纵坐标不变,再把得到的曲线向右平移 $\frac { \pi } { 6 }$ 个单位长度,得到曲线 ${ \sf C } _ { 2 }$ B. 把 $\mathsf C _ { 1 }$ 上各点的横坐标伸长到原来的2倍,纵坐标不变,再把得到的曲线向左平移 $\frac { \pi } { 1 2 }$ 个单位长度,得到曲线 ${ \sf C } _ { 2 }$ C. 把 $\mathsf C _ { 1 }$ 上各点的横坐标缩短到原来的 $\frac { 1 } { 2 }$ 倍,纵坐标不变,再把得到的曲线向右平移 $\frac { \pi } { 6 }$ 个单位长度,得到曲线 ${ \sf C } _ { 2 }$ D. 把 $^ { \mathrm { I } } { \mathsf { C } } _ { 1 }$ 上各点的横坐标缩短到原来的 $\frac 1 2$ 倍,纵坐标不变,再把得到的曲线向左平移 $\frac { \pi } { 1 2 }$ 个单位长度,得到曲线 ${ \sf C } _ { 2 }$
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 10 · Single choice · 中档
(5分)已知F为抛物线C: $y ^ { 2 } = 4 x$ 的焦点,过F作两条互相垂直的直线 $\mathsf { i } _ { 1 }$ , $\mathsf { I } _ { 2 } ;$ 直线 $\lvert \ l _ { 1 }$ 与C交于A、B两点,直线 $| | _ { 2 }$ 与C交于D、E两点,则 $\left| \mathsf { A B } \right| + \left| \mathsf { D E } \right|$ 的最小值为( )
A. 16 B. 14 C. 12 D. 10
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 11 · Free response · 中档
(5分)设x、y、z为正数,且 $2 ^ { x } = 3 ^ { y } = 5 ^ { z }$ ,则( )A $2 x { < } 3 y { < } 5 z$ B $5 z < 2 x < 3 y$ C $3 y < 5 z < 2 x$ D $3 y < 2 x < 5 z$
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 12 · Single choice · 中档
(5分)几位大学生响应国家的创业号召,开发了一款应用软件.为激发大家学习数学的兴趣,他们推出了“解数学题获取软件激活码”的活动.这款软件的激活码为下面数学问题的答案:已知数列1,1,2,1,2,4,1,2,4,8,1,2,4,8,16,…,其中第一项是2<sup>0</sup>,接下来的两项是2<sup>0</sup>,2<sup>1</sup>,再接下来的三项是2<sup>0</sup>,2<sup>1</sup>,2<sup>2</sup>,依此类推.求满足如下条件的最小整数N: $\mathsf { N } { \geq } 1 0$ 0且该数列的前N项和为2的整数幂.那么该款软件的激活码是( )
A. 440 B. 330 C. 220 D. 110
Submit answer
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 14 · Fill in the blank · 中档
(5分)设x,y满足约束条件$\begin{cases}x+2y\leqslant1\\2x+y\geqslant-1\\x-y\leqslant0\end{cases}$,则$z=3x-2y$的最小值为____.
先写答案,再对照解析 等价写法不自动判错
直接输入 Formula Chemistry
π ² √ ≤ ≥ ∞ ∈ ∴
写好了,对答案
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 17 · Free response · 中档
(12分) $\Delta A B C$ 的内角A,B,C的对边分别为a,b,c,已知 $\Delta A B C$ 的面积为$\frac { \mathsf { a } ^ { 2 } } { 3 \mathsf { s i n A } }$
(1)求sinBsinC;
(2)若 $6 \cos B \cos C = 1$ ,a=3,求 $\Delta A B C$ 的周长
Answer key See explanation
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?
Question 20 · Free response · 中档
(12分)已知椭圆C: $\frac { x ^ { 2 } } { a ^ { 2 } } + \frac { y ^ { 2 } } { b ^ { 2 } } = 1 ( a > b > 0 )$ ,四点 $\mathsf { P } _ { 1 } ( 1 , \ 1 ) \ , \ \mathsf { P } _ { 2 } ( 0 , \ 1$ ), $\mathsf { P } _ { 3 } \ ( \ - \ 1 , \ \frac { \sqrt { 3 } } { 2 } ) , \mathsf { P } _ { 4 } \ ( \ 1 , \ \frac { \sqrt { 3 } } { 2 } )$ 中恰有三点在椭圆C上
(1)求C的方程;
②设直线l不经过 ${ \sf P } _ { 2 }$ 点且与C相交于A,B两点.若直线 $\mathsf { P } _ { 2 } \mathsf { A } .$ 与直线 $\mathsf { P } _ { 2 } \mathsf { B }$ 的斜率的和为﹣1,证明:l过定点
Answer key See explanation
Did you get it? Got it Still lost
☆ Save
Spot a problem with this question?