gaokao

2015 sichuan-science

21 maths questions

1. Let set $A = \{ \mathrm { x } / ( \mathrm { x } + 1 ) ( \mathrm { x } - 2 ) < 0 \}$, set $B = \{ \mathrm { x } / 1 < \mathrm { x } < 3 \}$, then $A \cup B =$
A. $\{ X / - 1 < X < 3 \}$ B. $\{ X / - 1 < X < 1 \}$ C. $\{ X / 1 < X < 2 \}$ D. $\{ X / 2 < X < 3 \}$
Q2 Complex Numbers Arithmetic Complex Division/Multiplication Simplification View
2. Let $i$ be the imaginary unit, then the complex number $i ^ { 2 } - \frac { 2 } { i } =$
A. $-i$ B. $-3i$
C. $i$ D. $3 i$
Q3 Trig Graphs & Exact Values View
3. Execute the program flowchart shown in the figure, the output value of $S$ is
A. $- \frac { \sqrt { 3 } } { 2 }$ B. $\frac { \sqrt { 3 } } { 2 }$ C. $- \frac { 1 } { 2 }$ D. $\frac { 1 } { 2 }$ [Figure]
Q4 Trig Graphs & Exact Values View
4. Among the following functions, the one with minimum positive period $\pi$ and whose graph is symmetric about the origin is
A. $\mathrm { y } = \cos \left( 2 x + \frac { \pi } { 2 } \right)$
B. $y = \sin \left( 2 x + \frac { \pi } { 2 } \right)$
C. $y = \sin 2 x + \cos 2 x$
D. $y = \sin x + \cos x$
5. A line passing through the right focus of the hyperbola $x ^ { 2 } - \frac { y ^ { 2 } } { 3 } = 1$ and perpendicular to the $x$-axis intersects the two asymptotes of the hyperbola at points $\mathrm { A }$ and $\mathrm { B }$, then $| A B | =$
(A) $\frac { 4 \sqrt { 3 } } { 3 }$
(B) $2 \sqrt { 3 }$
(C) $6$
(D) $4 \sqrt { 3 }$
Q6 Permutations & Arrangements Forming Numbers with Digit Constraints View
6. Using the digits $0, 1, 2, 3, 4, 5$ to form five-digit numbers with no repeated digits, the number of even numbers greater than $40000$ is
(A) $144$
(B) $120$
(C) $96$
(D) $72$
Q7 Vectors Introduction & 2D Dot Product Computation View
7. Let quadrilateral $A B C D$ be a parallelogram, $| \overrightarrow { A B } | = 6$, $| \overrightarrow { A D } | = 4$. If points $\mathrm { M }$ and $\mathrm { N }$ satisfy $\overrightarrow { B M } = 3 \overrightarrow { M C }$, $\overrightarrow { D N } = 2 \overrightarrow { N C }$, then $\overrightarrow { A M } \cdot \overrightarrow { N M } =$
(A) $20$
(B) $15$
(C) $9$
(D) $6$
Q8 Laws of Logarithms Compare or Order Logarithmic Values View
8. Let $a$ and $b$ be positive numbers not equal to $1$. Then ``$3 ^ { a } > 3 ^ { b } > 3$'' is ``$\log _ { a } 3 < \log _ { b } 3$'' a
(A) necessary and sufficient condition
(B) sufficient but not necessary condition
(C) necessary but not sufficient condition
(D) neither sufficient nor necessary condition
9. If the function $f ( x ) = \frac { 1 } { 2 } ( m - 2 ) x ^ { 2 } + ( n - 8 ) x + 1$ $(m \geq 0, n \geq 0)$ is monotonically decreasing on the interval $\left[ \frac { 1 } { 2 }, 2 \right]$, then the maximum value of $m n$ is
(A) $16$
(B) $18$
(C) $25$
(D) $\frac { 81 } { 2 }$
10. Let line $l$ intersect the parabola $y ^ { 2 } = 4 x$ at points $\mathrm { A }$ and $\mathrm { B }$, and be tangent to the circle $( x - 5 ) ^ { 2 } + y ^ { 2 } = r ^ { 2 }$ $(r > 0)$ at point $M$, where $M$ is the midpoint of segment $A B$. If there are exactly $4$ such lines $l$, then the range of $r$ is
(A) $( 1, 3 )$
(B) $( 1, 4 )$
(C) $( 2, 3 )$
(D) $( 2, 4 )$
II. Fill in the Blanks
Q11 Binomial Theorem (positive integer n) Find a Specific Coefficient in a Single Binomial Expansion View
11. In the expansion of $( 2 x - 1 ) ^ { 8 }$, the coefficient of the term containing $x^4$ is $\_\_\_\_$ (answer with a number).
12. $\sin 15 ^ { \circ } + \sin 75 ^ { \circ } = \_\_\_\_$.
13. The shelf life $y$ (in hours) of a certain food and the storage temperature $x$ (in ${}^{\circ} \mathrm { C }$) satisfy the functional relationship $y = e ^ { k x + b }$ ($e = 2.718 \cdots$ is the base of the natural logarithm, $k$ and $b$ are constants). If the shelf life of this food at $0 ^ { \circ } \mathrm{C}$ is designed to be $192$ hours, and the shelf life at $22 ^ { \circ } \mathrm{C}$ is $45$ hours, then the shelf life of this food at $33 ^ { \circ } \mathrm{C}$ is $\_\_\_\_$ hours.
Q14 Vectors 3D & Lines MCQ: Angle Between Skew Lines View
14. As shown in the figure, quadrilaterals $ABCD$ and $ADPQ$ are both squares, and the planes they lie in are mutually perpendicular. A moving point $M$ is on segment $PQ$. $\mathrm { E }$ and $\mathrm { F }$ are the midpoints of $\mathrm { AB }$ and $\mathrm { BC }$ respectively. Let the angle between skew lines $EM$ and $AF$ be $\theta$, then the maximum value of $\cos \theta$ is $\_\_\_\_$. [Figure]
15. Given functions $f ( x ) = 2 ^ { x }$ and $g ( x ) = x ^ { 2 } + a x$ (where $a \in \mathbb{R}$). For unequal real numbers $x _ { 1 }$ and $x _ { 2 }$, let $m = \frac { f \left( x _ { 1 } \right) - f \left( x _ { 2 } \right) } { x _ { 1 } - x _ { 2 } }$ and $n = \frac { g \left( x _ { 1 } \right) - g \left( x _ { 2 } \right) } { x _ { 1 } - x _ { 2 } }$.
The following propositions are given:
(1) For any unequal real numbers $x _ { 1 }$ and $x _ { 2 }$, we have $m > 0$;
(2) For any $a$ and any unequal real numbers $x _ { 1 }$ and $x _ { 2 }$, we have $n > 0$;
(3) For any $a$, there exist unequal real numbers $x _ { 1 }$ and $x _ { 2 }$ such that $m = n$;
(4) For any $a$, there exist unequal real numbers $x _ { 1 }$ and $x _ { 2 }$ such that $m = - n$. The true propositions are $\_\_\_\_$ (write out the numbers of all true propositions).
III. Solution Questions
Q16 Sequences and series, recurrence and convergence Closed-form expression derivation View
16. Let the sequence $\left\{ a _ { n } \right\}$ have the sum of the first $n$ terms $S _ { n } = 2 a _ { n } - a _ { 3 }$, and $a _ { 1 }$, $a _ { 2 } + 1$, $a _ { 3 }$ form an arithmetic sequence.
(1) Find the general term formula of the sequence $\left\{ a _ { n } \right\}$;
(2) Let $T _ { n }$ be the sum of the first $n$ terms of the sequence $\left\{ \frac { 1 } { a _ { n } } \right\}$. Find the minimum value of $n$ such that $\left| T _ { n } - 1 \right| < \frac { 1 } { 1000 }$.
Q17 Combinations & Selection Combinatorial Probability View
17. Two schools A and B organize student teams to participate in a debate competition. School A recommends $3$ male students and $2$ female students, while school B recommends $3$ male students and $4$ female students. The students recommended by both schools participate in training. Since the students' levels are comparable after training, $3$ people are randomly selected from the male students and $3$ people are randomly selected from the female students to form a representative team.
(1) Find the probability that at least $1$ student from school A is selected for the representative team.
(2) Before a certain competition, $4$ people are randomly selected from the $6$ team members to participate. Let $X$ denote the number of male students participating, find the probability distribution and mathematical expectation of $X$.
Q18 Vectors 3D & Lines Multi-Part 3D Geometry Problem View
18. A net of a cube and a schematic diagram of the cube are shown in the figure. In the cube, let $M$ be the midpoint of $BC$ and $N$ be the midpoint of $GH$.
(1) Mark the letters $F$, $G$, $H$ at the corresponding vertices of the cube (no explanation needed).
(2) Prove: line $MN \parallel$ plane $BDH$.
(3) Find the cosine of the dihedral angle $A - E G - M$. [Figure]
19. As shown in the figure, $A$, $B$, $C$, $D$ are the four interior angles of quadrilateral $ABCD$.
(1) Prove: $\tan \frac { A } { 2 } = \frac { 1 - \cos A } { \sin A }$;
(2) If $A + C = 180 ^ { \circ }$, $AB = 6$, $BC = 3$, $CD = 4$, $AD = 5$, find the value of $\tan \frac { A } { 2 } + \tan \frac { B } { 2 } + \tan \frac { C } { 2 } + \tan \frac { D } { 2 }$. [Figure]
20. As shown in the figure, the ellipse $\mathrm { E } : \frac { x ^ { 2 } } { a ^ { 2 } } + \frac { y ^ { 2 } } { b ^ { 2 } } = 1$ $(a > b > 0)$ has eccentricity $\frac { \sqrt { 2 } } { 2 }$. A moving line $l$ passing through point $\mathrm { P } ( 0, 1 )$ intersects the ellipse at points $\mathrm { A }$ and $\mathrm { B }$. When line $l$ is parallel to the $x$-axis, the length of the chord intercepted by line $l$ on ellipse $E$ is $2 \sqrt { 2 }$.
(1) Find the equation of ellipse $E$;
(2) In the rectangular coordinate system $xOy$, does there exist a fixed point $Q$ different from point $P$ such that $\frac { | Q A | } { | Q B | } = \frac { | P A | } { | P B | }$ always holds? If it exists, find the coordinates of point $Q$; if it does not exist, explain the reason. [Figure]
Q21 Differentiating Transcendental Functions Determine intervals of increase/decrease or monotonicity conditions View
21. Given the function $f ( x ) = - 2 ( x + a ) \ln x + x ^ { 2 } - 2 a x - 2 a ^ { 2 } + a$, where $a > 0$.
(1) Let $g ( x )$ be the derivative of $f ( x )$. Discuss the monotonicity of $g ( x )$;
(2) Prove: there exists $a \in ( 0, 1 )$ such that $f ( x ) \geq 0$ holds on the interval $(1, + \infty)$, and $f ( x ) = 0$ has a unique solution in $(1, + \infty)$.