
1.已知集合\( A = \{1, 2\} \),\( B = \{-1, 0, 1, 2, 3\} \),则\( A \cap B = \)()
A.\(\{0, 1, 2, 3\}\)
B.\(\{1, 2, 3\}\)
C.\(\{0, 1, 2,\}\)
D.\(\{1, 2,\}\)
答案:D
2.函数\( f(x) = \frac{4}{\sqrt{3 - x}} \)的定义域为()
A.\(\{x|x > 3\}\)
B.\(\{x|x < 3\}\)
C.\(\{x|x > 4\}\)
D.\(\{x|x < 4\}\)
答案:B
3.已知向量a=(3,m),b=(2,-3),若a·b=0,则 m()
A.\(-1\)
B.\(-\frac{1}{2}\)
C.\(\frac{1}{2}\)
D.\(2\)
答案:D
4.在三角形\( ABC \)中,\( B = 120^{\circ} \),\( AB = 1 \),\( BC = 2 \),则\( AC = \)()
A.\(\sqrt{5}\)
B.\(\sqrt{6}\)
C.\(\sqrt{7}\)
D.\(2\sqrt{2}\)
答案:C
5.双曲线\( \frac{x^{2}}{20} - \frac{y^{2}}{5} = 1 \)的离心率为()
A.\(\frac{\sqrt{5}}{2}\)
B.\(\sqrt{5}\)
C.\(4\)
D.\(5\)
答案:A
6.不等式\( |-2x + 3| < 5 \)的解集为()
A.\((-\infty, -1)\)
B.\((-1, 4)\)
C.\((4, +\infty)\)
D.\((-\infty, -1) \cup (4, +\infty)\)
答案:B
7.函数\( y = f(x) \)的图像与函数\( y = 2^{x - 1} \)的图像关于\( x \)轴对称,则\( f(x) = \)()
A.\(2^{-x - 1}\)
B.\(-2^{x - 1}\)
C.\(2^{1 - x}\)
D.\(-2^{-x - 1}\)
答案:B
8.下列函数中,为增函数的是()
A.\( y = \sin 3x \)
B.\( y = 2e^{1 - x} \)
C.\( y = -\ln x \)
D.\( y = 2e^{2x - 1} \)
答案:D
9.抛物线\( y^{2} = 4x \)的焦点到直线\( 4x - 3y + 6 = 0 \)的距离是()
A.\(2\sqrt{5}\)
B.\(\frac{6\sqrt{5}}{5}\)
C.\(2\)
D.\(\frac{6}{5}\)
答案:C
10.已知\( a = \log_{5}3 \),\( b = 2^{0.4} \),\( c = \frac{1}{2} \),则()
A.\( c < b < a \)
B.\( a < c < b \)
C.\( c < a < b \)
D.\( a < b < c \)
答案:C
11.抛4枚质地均匀的硬币,恰好1枚硬币正面朝上的概率()
A.\(\frac{1}{4}\)
B.\(\frac{3}{8}\)
C.\(\frac{1}{2}\)
D.\(\frac{5}{8}\)
答案:A
12.设\( A \)、\( B \)为平面上的两个定点,\( P \)为该平面上的动点,若\( \overrightarrow{PA} \cdot \overrightarrow{PB} = 0 \),则\( P \)的轨迹为()
A.圆
B.椭圆
C.抛物线
D.双曲线
答案:A
13.数列\(\{ a_{n}\}\)中,\(a_{1}=1\),\(a_{n+1}=2a_{n}\),则\(a_{n}\)的前\(n\)项和为
答案:\(2^{n}-1\)
14.点\((m,n)\)在圆\(x^{2}+y^{2}-6x + 8y + 24 = 0\)上,则\(m^{2}+n^{2}\)的最小值为\(4\)
答案:4
15.有\(3\)个相同的球,编号为\(1\),\(2\),\(3\),从中有放回的随机取\(2\)次,每次取\(1\)个球,则编号为\(3\)的球恰好被取出\(1\)次的概率是
答案:\(\frac{4}{9}\)
16.已知函数\(f(x)=7\sin(\omega x + \frac{\pi}{3})(\omega > 0)\),其图像相邻两条对称轴之间的距离为\(3\)
(1)求\(\omega\)
(2)求\(f(x)\)在区间\([0,3]\)的最大值
答案:
解:(1)正弦函数相邻两条对称轴之间的距离为半个周期,所以周期\(T = 6\)
由\(T = \frac{2\pi}{\omega}\),得\(\omega = \frac{2\pi}{T} = \frac{2\pi}{6} = \frac{\pi}{3}\)
(2)由(1)得\(f(x)=7\sin(\frac{\pi}{3}x + \frac{\pi}{3})\)
当\(x \in [0,3]\)时,\(\frac{\pi}{3}x + \frac{\pi}{3} \in [\frac{\pi}{3},\frac{4\pi}{3}]\),函数在\([\frac{\pi}{3},\frac{\pi}{2}]\)上递增,在\([\frac{\pi}{2},\frac{4\pi}{3}]\)上递减
所以当\(\frac{\pi}{3}x + \frac{\pi}{3} = \frac{\pi}{2}\),即\(x = \frac{1}{2}\)时,\(\sin(\frac{\pi}{3}x + \frac{\pi}{3}) = 1\),\(f(x)\)的最大值为\(7\times1 = 7\)。
17.已知\(\{ a_{n}\}\)是等差数列,且\(a_{n+1}=pa_{n}-p\).
(1)若\(p = 3\),求\(a_{1}\)
(2)若\(\{ a_{n}\}\)的公差不为\(0\),求\(p\)
答案:
解:(1)设等差数列的公差为\(d\),则\(a_{n+1}=a_{n}+d\)
又\(a_{n+1}=3a_{n}-3\),所以\(a_{n}+d = 3a_{n}-3\),即\(2a_{n}-d - 3 = 0\),
因为对所有\(n\)成立,所以\(a_{n}\)是常数,即\(d = 0\)
则\(2a_{1}=3\),解得\(a_{1}=\frac{3}{2}\).
(2)由\(a_{n+1}=a_{n}+d = pa_{n}-p\),整理得\((p - 1)a_{n}-p - d = 0\)
因为对所有\(n\)成立且\(d \neq 0\),所以\(p - 1 = 0\)且\(-p - d = 0\)
由\(p - 1 = 0\)得\(p = 1\),带入\(-p - d = 0\)得\(d = -1 \neq 0\)符合条件,所以\(p = 1\).
18.已知函数\(f(x)=x + \frac{1}{3}ax^{3}\).
(1)求曲线\(f(x)\)在点\((0, f(0))\)处的切线方程.
(2)若\(a = -1\),求\(f(x)\)的单调区间.
答案:
解:(1)\(f(0) = 0\),求导\(f'(x) = 1 + ax^{2}\),\(f'(0) = 1\)
即斜率\(k = 1\),则切线方程为\(y - 0 = k(x - 0)\),即\(y = x\).
(2)\(a = -1\),则函数\(f(x) = x - \frac{1}{3}x^{3}\)
求导\(f'(x) = 1 - x^{2}\),令\(f'(x) = 0\),即\(1 - x^{2} = 0\)解得\(x = 1\)或\(x = -1\)
当\(-1 < x < 1\)时,\(f'(x) > 0\);当\(x < -1\)或\(x > 1\)时,\(f'(x) < 0\)
则\(f(x)\)的单调递增区间为\((-1, 1)\),单调递减区间为\((-\infty, -1)\)和\((1, +\infty)\).
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