gaokao

2015 chongqing-science

13 maths questions

1. Given sets $A = \{ 1,2,3 \} , B = \{ 2,3 \}$, then
A. $\mathrm { A } = \mathrm { B }$
B. $\mathrm { A } \cap \mathrm { B } = \varnothing$
C. $A \subset B$
D. $B \subset A$
Q2 Arithmetic Sequences and Series Find Specific Term from Given Conditions View
2. In the arithmetic sequence $\left\{ a _ { n } \right\}$, if $a _ { 2 } = 4 , a _ { 4 } = 2$, then $a _ { 6 } =$
A. $-1$
B. $0$
C. $1$
D. $6$
Q3 Data representation View
3. The stem-and-leaf plot below shows the average monthly temperatures (${ } ^ { \circ } C$) in Chongqing in 2013:
The median of this data set is
A. $19$
B. $20$
C. $21.5$
D. $23$
4. ``$\mathrm { x } > 1$'' is ``$\log _ { \frac { 1 } { 2 } } ( \mathrm { x } + 2 ) < 0$'' a
A. necessary and sufficient condition
B. sufficient but not necessary condition
C. necessary but not sufficient condition
D. neither sufficient nor necessary condition
Q6 Vectors Introduction & 2D Angle or Cosine Between Vectors View
6. If non-zero vectors $\mathbf { a } , \mathbf { b }$ satisfy $| \mathbf { a } | = \frac { 2 \sqrt { 2 } } { 3 } | \mathbf { b } |$ and $(\mathbf{a}-\mathbf{b})\perp(3\mathbf{a}+2\mathbf{b})$, then the angle between $\mathbf { a }$ and $\mathbf { b }$ is
A. $\frac { \pi } { 4 }$
B. $\frac { \pi } { 2 }$
C. $\frac { 3 \pi } { 4 }$
D. $\pi$
8. Given that the line $l$: $x + a y - 1 = 0 ( a \in R )$ is an axis of symmetry of the circle $C$: $x ^ { 2 } + y ^ { 2 } - 4 x - 2 y + 1 = 0$. A tangent line to circle $C$ is drawn from point $\mathrm { A } ( - 4 , \mathrm { a } )$, with tangent point $B$. Then $| \mathrm { AB } | =$
A. $2$
B. $4 \sqrt { 2 }$
C. $6$
D. $2 \sqrt { 10 }$
9. If $\tan \alpha = 2 \tan \frac { \pi } { 5 }$, then $\frac { \cos \left( \alpha - \frac { 3 \pi } { 10 } \right) } { \sin \left( \alpha - \frac { \pi } { 5 } \right) } =$
A. $1$
B. $2$
C. $3$
D. $4$
10. Let the hyperbola $\frac { x ^ { 2 } } { a ^ { 2 } } - \frac { y ^ { 2 } } { b ^ { 2 } } = 1 ( \mathrm { a } > 0 , \mathrm {~b} > 0 )$ have right focus $F$. A line through $F$ perpendicular to $AF$ intersects the hyperbola at points $\mathrm { B }$ and $\mathrm { C }$. Lines through $\mathrm { B }$ and $\mathrm { C }$ perpendicular to $\mathrm { AC }$ and $\mathrm { AB }$ respectively intersect at point $D$. If the distance from $D$ to line $BC$ is less than $a + \sqrt { a ^ { 2 } + b ^ { 2 } }$, then the range of the slope of the asymptotes of the hyperbola is
A. $( - 1,0 ) \cup ( 0,1 )$
B. $( - \infty , - 1 ) \cup \left( 1 , + \infty \right)$
C. $( - \sqrt { 2 } , 0 ) \cup ( 0 , \sqrt { 2 } )$
D. $( - \infty , - \sqrt { 2 } ) \cup ( \sqrt { 2 } , + \infty )$
II. Fill-in-the-Blank Questions: This section contains 6 questions. Candidates answer 5 of them, each worth 5 points, for a total of 25 points. Write your answers in the corresponding positions on the answer sheet.
Q11 Complex Numbers Arithmetic Modulus Computation View
11. If the modulus of the complex number $\mathrm { a } + \mathrm { bi } ( \mathrm { a } , \mathrm { b } \in \mathrm { R } )$ is $\sqrt { 3 }$, then $( \mathrm { a } + \mathrm { bi } ) ( \mathrm { a } - \mathrm { bi } ) = $ $\_\_\_\_$ .
Q12 Binomial Theorem (positive integer n) Find a Specific Coefficient in a Single Binomial Expansion View
12. The coefficient of $x ^ { 8 }$ in the expansion of $\left( x ^ { 3 } + \frac { 1 } { 2 \sqrt { x } } \right) ^ { 5 }$ is $\_\_\_\_$ (answer with numerals).
Q13 Sine and Cosine Rules Multi-step composite figure problem View
13. In $\triangle \mathrm { ABC }$, $\mathrm { B } = 120 ^ { \circ } , \mathrm { AB } = \sqrt { 2 }$, and the angle bisector from $A$ is $\mathrm { AD } = \sqrt { 3 }$, then $\mathrm { AC } = $ $\_\_\_\_$ . Note for Candidates: Questions (14), (15), and (16) are optional. Please choose any two to answer. If all three are answered, only the first two will be graded.
14. As shown in question (14), chords $\mathrm { AB }$ and $\mathrm { CD }$ of circle $O$ intersect at point $E$. A tangent line to circle $O$ is drawn through point $A$ and intersects the extension of $DC$ at point $P$. If $P A = 6 , A E = 9 , P C = 3 , C E : E D = 2 : 1$, then $B E = $ $\_\_\_\_$ . [Figure]
Q15 Polar coordinates View
15. The parametric equation of line $l$ is $\left\{ \begin{array} { c } x = - 1 + t \\ y = 1 + t \end{array} \right.$ (where $t$ is the parameter). With the origin as the pole and the positive $x$-axis as the polar axis, the polar equation of curve $C$ is $\rho ^ { 2 } \cos 2 \theta = 4 \left( \rho > 0 , \frac { 3 \pi } { 4 } < \theta < \frac { 5 \pi } { 4 } \right)$. The polar coordinates of the intersection point of line $l$ and curve $C$ are $\_\_\_\_$ .
16. If the minimum value of the function $f ( x ) = | x + 1 | + 2 | x - a |$ is 5, then the real number $a = $ $\_\_\_\_$ . III. Solution Questions: This section contains 6 questions, for a total of 75 points. Show your work, proofs, or calculation steps. (17) (This question is worth 13 points: part (I) is worth 5 points, part (II) is worth 8 points) Eating zongzi on Dragon Boat Festival is a traditional custom in China. A plate contains 10 zongzi: 2 with red bean paste, 3 with meat, and 5 plain. The three types of zongzi look identical. Three zongzi are randomly selected. (I) Find the probability that one zongzi of each type is selected. (II) Let $X$ denote the number of red bean paste zongzi selected. Find the probability distribution and mathematical expectation of $X$. (18) (This question is worth 13 points: part (I) is worth 7 points, part (II) is worth 6 points) Given the function $f ( x ) = \sin \left( \frac { \pi } { 2 } - x \right) \sin x - \sqrt { 3 } \cos ^ { 2 } x$ (I) Find the minimum positive period and maximum value of $f ( x )$. (II) Discuss the monotonicity of $f ( x )$ on $\left[ \frac { \pi } { 6 } , \frac { 2 \pi } { 3 } \right]$. (19) (This question is worth 13 points: part (I) is worth 4 points, part (II) is worth 9 points) As shown in question (19), in the triangular pyramid $P - A B C$, $P C \perp$ plane $A B C$, $P C = 3$, $\angle A C B = \frac { \pi } { 2 }$. Points $D$ and $E$ are on segments $A B$ and $B C$ respectively, with $C D = D E = \sqrt { 2 }$, $C E = 2 E B = 2$. (I) Prove that $D E \perp$ plane $P C D$. (II) Find the cosine of the dihedral angle $A - P D - C$. (20) (This question is worth 12 points: part (I) is worth 7 points, part (II) is worth 5 points) Let the function $f ( x ) = \frac { 3 x ^ { 2 } + a x } { e ^ { x } } ( a \in R )$. (I) If $f ( x )$ has an extremum at $x = 0$, determine the value of $a$ and find the equation of the tangent line to the curve $y = f ( x )$ at the point $( 1 , f ( 1 ) )$. (II) If $f ( x )$ is decreasing on $[ 3 , + \infty )$, find the range of values for $a$. (21) (This question is worth 12 points: part (I) is worth 5 points, part (II) is worth 7 points)
[Figure]
Question (19) Figure
As shown in question (21), the ellipse $\frac { x ^ { 2 } } { a ^ { 2 } } + \frac { y ^ { 2 } } { b ^ {