gaokao

2018 national-II-arts

20 maths questions

Q1 5 marks Complex Numbers Arithmetic Complex Division/Multiplication Simplification View
$i ( 2 + 3 i ) =$
A. $3 - 2 \mathrm { i }$
B. $3 + 2 i$
C. $- 3 - 2 \mathrm { i }$
D. $- 3 + 2 \mathrm { i }$
Q2 5 marks Probability Definitions Set Operations View
Given sets $A = \{ 1,3,5,7 \} , B = \{ 2,3,4,5 \}$, then $A \cap B =$
A. $\{ 3 \}$
B. $\{ 5 \}$
C. $\{ 3,5 \}$
D. $\{ 1,2,3,4,5,7 \}$
Q3 5 marks Curve Sketching Identifying the Correct Graph of a Function View
The graph of the function $f ( x ) = \frac { \mathrm { e } ^ { x } - \mathrm { e } ^ { - x } } { x ^ { 2 } }$ is approximately (see options A, B, C, D in the figures).
Q4 5 marks Vectors Introduction & 2D Dot Product Computation View
Vectors $\boldsymbol { a } , \boldsymbol { b }$ satisfy $| \boldsymbol { a } | = 1 , \boldsymbol { a } \cdot \boldsymbol { b } = - 1$, then $\boldsymbol { a } \cdot ( 2 \boldsymbol { a } - \boldsymbol { b } ) =$
A. 4
B. 3
C. 2
D. 0
Q5 5 marks Combinations & Selection Combinatorial Probability View
From 2 male students and 3 female students, 2 people are selected to participate in community service. The probability that both selected are female students is
A. 0.6
B. 0.5
C. 0.4
D. 0.3
Q6 5 marks Conic sections Eccentricity or Asymptote Computation View
The hyperbola $\frac { x ^ { 2 } } { a ^ { 2 } } - \frac { y ^ { 2 } } { b ^ { 2 } } = 1 ( a > 0 , b > 0 )$ has eccentricity $\sqrt { 3 }$. Its asymptotes are
A. $y = \pm \sqrt { 2 } x$
B. $y = \pm \sqrt { 3 } x$
C. $y = \pm \frac { \sqrt { 2 } } { 2 } x$
D. $y = \pm \frac { \sqrt { 3 } } { 2 } x$
Q7 5 marks Sine and Cosine Rules Find a side length using the cosine rule View
In $\triangle A B C$, $\cos \frac { C } { 2 } = \frac { \sqrt { 5 } } { 5 } , B C = 1 , A C = 5$, then $A B =$
A. $4 \sqrt { 2 }$
B. $\sqrt { 30 }$
C. $\sqrt { 29 }$
D. $2 \sqrt { 5 }$
Q9 5 marks Vectors 3D & Lines MCQ: Angle Between Skew Lines View
In the rectangular prism $A B C D - A _ { 1 } B _ { 1 } C _ { 1 } D _ { 1 }$, $E$ is the midpoint of edge $C C _ { 1 }$. The tangent of the angle between skew lines $A E$ and $C D$ is
A. $\frac { \sqrt { 2 } } { 2 }$
B. $\frac { \sqrt { 3 } } { 2 }$
C. $\frac { \sqrt { 5 } } { 2 }$
D. $\frac { \sqrt { 7 } } { 2 }$
Q10 5 marks Addition & Double Angle Formulae Function Analysis via Identity Transformation View
If $f ( x ) = \cos x - \sin x$ is decreasing on $[ 0 , a ]$, then the maximum value of $a$ is
A. $\frac { \pi } { 4 }$
B. $\frac { \pi } { 2 }$
C. $\frac { 3 \pi } { 4 }$
D. $\pi$
Q11 5 marks Conic sections Eccentricity or Asymptote Computation View
Let $F _ { 1 } , F _ { 2 }$ be the two foci of ellipse $C$. $P$ is a point on $C$. If $P F _ { 1 } \perp P F _ { 2 }$ and $\angle P F _ { 2 } F _ { 1 } = 60 ^ { \circ }$, then the eccentricity of $C$ is
A. $1 - \frac { \sqrt { 3 } } { 2 }$
B. $2 - \sqrt { 3 }$
C. $\frac { \sqrt { 3 } - 1 } { 2 }$
D. $\sqrt { 3 } - 1$
Q12 5 marks Sequences and Series Evaluation of a Finite or Infinite Sum View
Let $f ( x )$ be an odd function with domain $( - \infty , + \infty )$, satisfying $f ( 1 - x ) = f ( 1 + x )$ and $f ( 1 ) = 2$. Then $f ( 1 ) + f ( 2 ) + f ( 3 ) + \cdots + f ( 50 ) =$
A. $- 50$
B. $0$
C. $2$
D. $50$
Q13 5 marks Tangents, normals and gradients Find tangent line equation at a given point View
The equation of the tangent line to the curve $y = 2 \ln x$ at the point $( 1,0 )$ is \_\_\_\_.
Q14 5 marks Inequalities Linear Programming (Optimize Objective over Linear Constraints) View
Given the constraints $\left\{ \begin{array} { l } x + 2 y - 5 \geq 0 , \\ x - 2 y + 3 \geq 0 , \\ x - 5 \leq 0 , \end{array} \right.$ the minimum value of $z = x + y$ is \_\_\_\_.
Q15 5 marks Addition & Double Angle Formulae Addition/Subtraction Formula Evaluation View
Given $\tan \left( \alpha - \frac { 5 \pi } { 4 } \right) = \frac { 1 } { 5 }$, then $\tan \alpha = $ \_\_\_\_ .
Q17 12 marks Arithmetic Sequences and Series Multi-Part Structured Problem on AP View
Let $S _ { n }$ be the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$. Given $a _ { 1 } = - 7 , S _ { 3 } = - 15$.
(1) Find the general term formula for $\left\{ a _ { n } \right\}$;
(2) Find $S _ { n }$ and the minimum value of $S _ { n }$.
Q18 12 marks Linear regression View
The figure below is a line graph of environmental infrastructure investment $y$ (in units of 100 million yuan) from 2000 to 2016 in a certain region.
To predict the environmental infrastructure investment in 2018 for this region, two linear regression models for $y$ and time variable $t$ were established. Based on data from 2000 to 2016 (time variable $t$ takes values $1,2 , \cdots , 17$ respectively), Model (1) was established: $\hat { y } = - 30.4 + 13.5 t$. Based on data from 2010 to 2016 (time variable $t$ takes values $1,2 , \cdots , 7$ respectively), Model (2) was established: $\hat { y } = 99 + 17.5 t$.
(1) Using each of these two models, find the predicted value of environmental infrastructure investment for 2018 in this region;
(2) Which model's prediction do you think is more reliable? Explain your reasoning.
Q19 12 marks Vectors: Lines & Planes Distance Computation (Point-to-Plane or Line-to-Line) View
As shown in the figure, in the triangular pyramid $P - A B C$, $A B = B C = 2 \sqrt { 2 }$, $P A = P B = P C = A C = 4$, and $O$ is the midpoint of $A C$.
(1) Prove: $P O \perp$ plane $A B C$;
(2) If point $M$ is on edge $B C$ such that $M C = 2 M B$, find the distance from point $C$ to plane $P O M$.
Q20 12 marks Conic sections Circle-Conic Interaction with Tangency or Intersection View
Let the parabola $C : y ^ { 2 } = 4 x$ have focus $F$. A line $l$ through $F$ with slope $k ( k > 0 )$ intersects $C$ at points $A , B$, with $| A B | = 8$.
(1) Find the equation of $l$;
(2) Find the equation of the circle passing through points $A , B$ and tangent to the directrix of $C$.
Q21 12 marks Stationary points and optimisation Determine intervals of increase/decrease or monotonicity conditions View
Given the function $f ( x ) = \frac { 1 } { 3 } x ^ { 3 } - a \left( x ^ { 2 } + x + 1 \right)$.
(1) When $a = 3$, find the monotonic intervals of $f ( x )$;
(2) Prove: $f ( x )$ has exactly one zero.
Q22 10 marks Parametric curves and Cartesian conversion View
[Elective 4-4: Polar Coordinates and Parametric Equations]
In the rectangular coordinate system $x O y$, the parametric equation of curve $C$ is $\left\{ \begin{array} { l } x = 2 \cos \theta , \\ y = 4 \sin \theta \end{array} \right.$ ($\theta$ is the parameter). The parametric equation of line $l$ is $\left\{ \begin{array} { l } x = 1 + t \cos \alpha , \\ y = 2 + t \sin \alpha \end{array} \right.$ ($t$ is the parameter).
(1) Find the rectangular coordinate equations of $C$ and $l$;
(2) If the midpoint of the line segment obtained by the intersection of curve $C$ and line $l$ is $( 1,2 )$, find the slope of $l$.