gaokao

2015 hunan-arts

20 maths questions

Q1 Complex Numbers Arithmetic Solving Equations for Unknown Complex Numbers View
1. Given $\frac { ( 1 - j ) ^ { 2 } } { z } = 1 + \mathrm { i }$ (where i is the imaginary unit), then the complex number $\mathrm { z } =$
Q2 Data representation Selection and Task Assignment View
2. In a marathon competition, the stem-and-leaf plot in Figure 1 shows the results (in minutes) of 35 athletes. [Figure]
If the athletes are numbered 1-35 according to their results from best to worst, and 7 people are selected using systematic sampling, then the number of athletes with results in the interval [139, 151] is
A. 3
B. 4
C. 5
D. 6
3. Let $x \in R$. Then ``$x > 1$'' is ``$x ^ { 3 } > 1$'' a
A. sufficient but not necessary condition
B. necessary but not sufficient condition
C. necessary and sufficient condition
D. neither sufficient nor necessary condition
4. If variables $x , y$ satisfy the constraint conditions $\left\{ \begin{array} { c } x + y \geq 1 , \\ y - x \leq 1 , \text { then } z = 2 x - y \text { has a minimum value of } \\ x \leq 1 , \end{array} \right.$
A. $-1$
B. 0
C. 1
D. 2
Q5 Arithmetic Sequences and Series Flowchart or Algorithm Tracing Involving Sequences View
5. Executing the flowchart shown in Figure 2, if the input is $n = 3$, then the output $S =$
A. $\frac { 6 } { 7 }$
B. $\frac { 3 } { 7 }$
C. $\frac { 8 } { 9 }$
D. $\frac { 4 } { 9 }$
[Figure]
Figure 2
6. If one asymptote of the hyperbola $\frac { x ^ { 2 } } { a ^ { 2 } } - \frac { y ^ { 2 } } { b ^ { 2 } } = 1$ passes through the point $( 3 , - 4 )$, then the eccentricity of this hyperbola is
A. $\frac { \sqrt { 7 } } { 3 }$
B. $\frac { 5 } { 4 }$
C. $\frac { 4 } { 3 }$
D. $\frac { 5 } { 3 }$
Q7 Inequalities Ratio and Proportion Problems View
7. If real numbers $\mathrm { a } , \mathrm { b }$ satisfy $\frac { 1 } { a } + \frac { 2 } { b } = \sqrt { a b }$, then the minimum value of $ab$ is
A. $\sqrt { 2 }$
B. 2
C. $2 \sqrt { 2 }$
D. 4
Q8 Function Transformations View
8. Let the function $f ( x ) = \ln ( 1 + x ) - \ln ( 1 - x )$. Then $f ( x )$ is
A. an odd function and increasing on $( 0,1 )$
B. an odd function and decreasing on $( 0,1 )$
C. an even function and increasing on $( 0,1 )$
D. an even function and decreasing on $( 0,1 )$
Q9 Vectors Introduction & 2D Optimization of a Vector Expression View
9. Points $\mathrm { A } , \mathrm { B } , \mathrm { C }$ move on the circle $\chi ^ { 2 } + y ^ { 2 } = 1$, and $\mathrm { AB } \perp \mathrm { BC }$. If point P has coordinates $( 2,0 )$, then the maximum value of $| \overrightarrow { P A } + \overrightarrow { P B } + \overrightarrow { P C } |$ is
A. 6
B. 7
C. 8
D. 9
Q11 Probability Definitions Set Operations View
11. Given the set $\mathrm { U } = \{ 1,2,3,4 \} , \mathrm { A } = \{ 1,3 \} , \mathrm { B } = \{ 1,3,4 \}$, then $\mathrm { A } \cup ( C \cup B ) =$ $\_\_\_\_$
12. In the rectangular coordinate system xOyz, with the coordinate origin as the pole and the positive x-axis as the polar axis, if the polar equation of curve C is $\rho = 3 \sin \theta$, then the rectangular coordinate equation of curve C is $\_\_\_\_$
13. If the line $3 x - 4 y + 5 = 0$ intersects the circle $x ^ { 2 } + y ^ { 2 } = r ^ { 2 } \quad ( r > 0 )$ at points $A$ and $B$, and $\angle A O B = 120 ^ { \circ }$ (where O is the coordinate origin), then $r =$ $\_\_\_\_$.
14. If the function $f ( x ) = \left| 2 ^ { x } - 2 \right| - b$ has two zeros, then the range of the real number $b$ is $\_\_\_\_$
Q15 Trig Graphs & Exact Values Function Analysis via Identity Transformation View
15. Given $w > 0$, the two closest intersection points of the graphs of $y = 2 \sin w x$ and $y = 2 \cos w x$ have a distance of $2 \sqrt { 3 }$. Then $w =$ $\_\_\_\_$.
III. Solution Questions: This section has 6 questions, for a total of 75 points. Solutions should include written explanations, proofs, or calculation steps.
Q16 Probability Definitions Finite Equally-Likely Probability Computation View
16. (This question is worth 12 points)
A shopping mall is holding a promotional lottery activity. After customers purchase goods of a certain amount, they can participate in the lottery. The lottery method is as follows: randomly draw 1 ball each from box A containing 2 red balls $\mathrm { A } _ { 1 } , \mathrm { A } _ { 2 }$ and 1 white ball B, and from box B containing 2 red balls $\mathrm { a } _ { 1 } , \mathrm { a } _ { 2 }$ and 2 white balls $\mathrm { b } _ { 1 } , \mathrm { b } _ { 2 }$. If both balls drawn are red, the customer wins; otherwise, the customer does not win. (I) List all possible outcomes of drawing balls using the ball labels. (II) Someone claims: Since there are more red balls than white balls in both boxes, the probability of winning is greater than the probability of not winning. Do you agree? Please explain your reasoning.
17. (This question is worth 12 points) Let the sides opposite to angles $A , B , C$ of $\triangle A B C$ be $a , b , c$ respectively, with $a = b \tan A$. (I) Prove that: $\sin \mathrm { B } = \cos \mathrm { A }$ (II) If $\sin C - \sin A \cos B = \frac { 3 } { 4 }$ and $B$ is an obtuse angle, find $A$, $B$, and $C$.
Q18 Vectors 3D & Lines Multi-Part 3D Geometry Problem View
18. (This question is worth 12 points) As shown in Figure 4, the right triangular prism $\mathrm { ABC } - \mathrm { A } _ { 1 } \mathrm { B } _ { 1 } \mathrm { C } _ { 1 }$ has an equilateral triangle base with side length 2. $\mathrm { E }$ and $\mathrm { F }$ are the midpoints of $\mathrm { BC }$ and $\mathrm { CC } _ { 1 }$ respectively. (I) Prove that: plane $\mathrm { AEF } \perp$ plane $\mathrm { B } _ { 1 } \mathrm { BCC } _ { 1 }$ (II) If the angle between line $A _ { 1 } C$ and plane $A _ { 1 } A B B _ { 1 }$ is $45 ^ { \circ }$, find the volume of the triangular pyramid F-AEC. [Figure]
Q19 Sequences and series, recurrence and convergence Closed-form expression derivation View
19. (This question is worth 13 points) Let $S _ { n }$ be the sum of the first $n$ terms of the sequence $\left\{ a _ { n } \right\}$. Given $a _ { 1 } = 1 , a _ { 2 } = 2$, and $a _ { n + 2 } = 3 S _ { n } - S _ { n + 1 } , n \in \mathbb { N } ^ { * }$. (I) Prove that: $a _ { n + 2 } = 3 a _ { n }$ (II) Find $\mathrm { S } _ { \mathrm { n } }$
20. (This question is worth 13 points) The focus F of the parabola $\mathrm { C } _ { 1 } : \mathrm { X } ^ { 2 } = 4 \mathrm { y }$ is also a focus of the ellipse $\mathrm { C } _ { 2 } : \frac { y ^ { 2 } } { a ^ { 2 } } + \frac { X ^ { 2 } } { b ^ { 2 } } = 1 ( \mathrm { a } > \mathrm { b } > 0 )$. The common chord of $\mathrm { C } _ { 1 }$ and $\mathrm { C } _ { 2 }$ has length $2 \sqrt { 6 }$. A line $l$ through point F intersects $\mathrm { C } _ { 1 }$ at points $\mathrm { A } , \mathrm { B }$ and intersects $\mathrm { C } _ { 2 }$ at points $\mathrm { C } , \mathrm { D }$, with $\overrightarrow { B D }$ and $\overrightarrow { A C }$ in the same direction.
(1) Find the equation of $\mathrm { C } _ { 2 }$;
(2) If $| \mathrm { AC } | = | \mathrm { BD } |$, find the slope of line $l$.
Q21 Differentiating Transcendental Functions Qualitative Analysis of DE Solutions View
21. (This question is worth 13 points) Given $\mathrm { a } > 0$, the function $\mathrm { f } ( \mathrm { x } ) = \mathrm { a } e ^ { x } \cos x$ for $\mathrm { x } \in [ 0 , + \infty )$. Let $x _ { n }$ denote the $n$-th (where $n \in \mathbb { N } ^ { * }$) extremum point of $f ( x )$ in increasing order. (I) Prove that: the sequence $\left\{ f \left( \mathrm { x } _ { \mathrm { n } } \right) \right\}$ is a geometric sequence; (II) If for all $n \in \mathbb { N } ^ { * }$, the inequality $x _ { n } \leq \left| f \left( x _ { n } \right) \right|$ always holds, find the range of $a$.