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高三数学
【解析】 p:m0,考虑q:g(m)0
.
参考答案及解析 当m2时,g(m)0等价于0m2,
当m2时,g(m)0等价于log m1,
1.【答案】C a
【解析】由A x|12x 16,xZ ,得A 0,1,2,3,4 , 由已知: p是q的必要不充分条件,得存在m2,使得log m1.
a
x3 0a1时,对任意的m2,log m01成立;
由B x 0,得B x|1 x3 ,所以AB2,3 . a
x1
a 1时,m2,(log m) log 2,因此log 21 a2.
a min a a
故选:C.
综上:0a1或a2.
2.【答案】D
z
故选:B.
【解析】由 1i,得z3i,所以|z2i|3 2.
2i
7.【答案】C
故选:D.
2 T kT 8
【解析】由三角函数的图象与性质可得 ( ) ,kZ,解得T ,kZ,又因为
3.【答案】D
3 3 3 4 2 3(12k)
【解析】易知圆锥的底面半径 R 2 ,母线l 2,所以圆锥的表面积S πR2 πRl 22 2 π. T 3 ,2 ,故有且仅有k 1时满足题意,此时T 2 8 ,解得 9 ,此时 f xsin( 9x ),代入x= ,
4 9 4 4 3
故选:D.
可得
3
k ’,k ’Z,又因为2,故有且仅有k ’1时满足题意,此时
7
.故
63
.
4.【答案】B 4 4 16
a a a
故选:C.
【解析】 4 5 6 q3 8 ,a a a 56
a a a 4 5 6 .
1 2 3 8.【答案】D
故选:B.
【解析】设 f(t)et et ,则 f(x)e2 2e, f(y)e33e, f(z)e55e ,
5.【答案】C
1 1 因为 f(t)et e, f(t)在定义域上单调递增,又 f(1)0,所以 f(t)在(1,)上单调递增,在(,1)上单
1 tan()tan 2 7 1
【解析】由题意可得tan ,且tantan[()] ,故
调递减,
7 1tan()tan 1 1 3
1
2 7
且 f(x) f(2), f(y) f(3), f(z) f(5),x 2,y 3,z 5.
1
2
2tan 3 3 所以 f(x) f(y) f(z)(x1,y1,z1),
tan2 .
1tan2 1 2 4
1
故z y x.
3
故选:D.
9.【答案】BD
故选:C.
【解析】将样本数据按照从小到大的顺序排列为:6,11,12,16,17,19,31.
6.【答案】B
对于A,根据极差定义可知,该组数据的极差为31625,故A错误;
第 1 页 共 6 页A
所以sin Acos ,································· ·························································2分 f(x)是增函数,即 f(x)0在(0,+∞)上恒成立, ………………………………………………8分
2
A A A
所以2sin cos cos ,··················································································4分 方法一:即axxlnx在(0,+∞)上恒成立,所以axxlnx ,
2 2 2 max
A π A 设g(x)xxlnx,x>0,则g(x)2lnx,x>0,………………………………………………11分
因为A(0,π),所以 0, ,所以cos 0,·······················································5分
2 2 2
1
A 1 A π π 当x 0, 时,g(x)0,g(x)单调递增,
所以sin ,解得 ,即A .····································································6分 e2
2 2 2 6 3
1
当x
, 时,g(x)0,g(x)单调递减,
(备注:推导出sinAcos A 给2分;推导出sin A 1 给3分,得出角A的大小给1分) e2
2 2 2
(2)因为D为BC的中点, ∴当x 1 时,g(x)取得极大值,也是最大值,∵g 1 1 ,……………………………………14分
e2 e2 e2
1
所以AD (ABAC),·························································································8分
2
1
∴a的取值范围是
,. ……………………………………………………………………………15分
7 e2
又AD ,b2,
2
(备注:得出 f '(x)≥0在(0,+∞)恒成立给2分;分离参数给1分,得出g(x)的最大值给5分;下结论给1分,
7 1
两边平方得到 (c2 42c),整理可得c2 2c30,···········································10分
过程酌情给分)
4 4
解得c1或c3(舍去)······················································································11分
a a
方法二:即lnx 10在(0,+∞)上恒成立,所以lnx 1 0,
x x
1 3 min
所以ABC的面积S bcsinA .·····································································13分
2 2 a 1 a xa
设h(x)lnx 1,x>0,则h(x) ,x>0,………………………………………9分
x x x2 x2
(备注:写出中线定理 A D 1 ( A B A C )给2分;求出c=1给3分;得出三角形面积给2分)
2 ①若a0,则h(x)0,h(x)在(0,)上单调递增,
1
16.【答案】(1)2xy20(6分) (2)
, (9分) 当x趋近于0时,h(x)趋近于,即 f(x)0不恒成立,
e2
x1 1
所以 f(x)在(0,)上不单调递增,与题意不符,舍去.………………………………………………11分
【解析】(1)当a1时, f(x)(x1)lnx, f(x)lnx lnx 1, …………………2分
x x ②若a0,则
f(1)0, f(1)2, …………………………………………………………………………………4分
当x(0,a)时,h(x)0,h(x)单调递减,
∴曲线 y f(x)在(1, f(1))处的切线方程为y f(1) f(1)(x1),
当x(a,)时,h(x)0,h(x)单调递增,
整理得,y2(x1),
则当xa时,h(x)取得极小值,也是最小值,
∴曲线 y f(x)在(1, f(1))处的切线方程为2xy20. ………………………………………6分
∴h(a)lna20,
(备注:求导给2分;求出斜率和切点给2分;求出切线方程给2分)
1
解得a ,………………………………………………………………………………………………14分
xa a e2
(2) f(x)lnx lnx 1,x>0,
x x
第 3 页 共 6 页 1 1 3
∴a的取值范围是 e2 , . …………………………………………………………………………15分 n 1 AC 0 4 x 4 y 0,
设平面CDA的法向量为n (x,y,z),则 ····························10分
1 1 3
(备注:得出 f '(x)≥0在(0,+∞)恒成立给2分;构造h(x)给1分;令h(x) min ≥0求a的取值范围给5分,未讨 n 1 AD 0 2 x 2 z 0,
论a的正负扣2分;下结论给1分,过程酌情给分)
令x3,得 y 3,z 3,所以n (3, 3, 3),··················································11分
1
2 5
17.【答案】(1)证明见解析 (6分)(2) (9分) 易知平面EDA的一个法向量为n (0,1,0),································ ······························12分
2
5
n n 3 5
【解析】(1)证明:因为ABC为正三角形,且D,E,F分别是各边的中点, 所以cosn,n 1 2 ,····························································14分
1 2 |n ||n | 151 5
1 2
所以ADE,CDF,BEF 均为正三角形.
2 5
所以二面角CDAE的正弦值为 .····································································15分
5
分别取DE,EF,FD的中点A,B ,C ,
1 1 1
(备注:建系给1分;写出点的坐标给1分;写出平面EDA的法向量给1分;计算出平面CDA的法向量给3分;
则AA DE,BB EF,CC DF ,AA BB CC ,·················································1分
1 1 1 1 1 1
求出二面角的正弦值给3分,过程酌情给分)
又因为平面ADE 底面DEF ,平面ADE 底面DEF DE,
1 2
18.【答案】(1) p 0, p (4分)(2) p(Y 1| X 2) (5分)
所以AA 平面DEF ,同理可得BB 平面DEF ,······················································3分 (2,0) (2,1) 9 3
1 1
所以 ,·································································································4分 (3)分布列见解析(8分)
AA BB
1 1
【解析】(1)X 2,Y 0的情况有,甲抢到2题并答对2题,乙未抢到题,不符合题意;甲抢到2题并答对
所以四边形AABB为平行四边形,所以AB AB ,
1 1 1 1
2题,乙抢到2题并答对1题答错1题,不符合题意.
因为AB平面DEF ,AB 平面DEF ,所以AB平面DEF .··································5分
1 1 所以 p 0,··········································································································2分
(2,0)
同理可得CB平面DEF , X 2,Y 1的情况有,甲抢到2题并答对2题,乙抢到1题并答错1题,
又ABBC B,AB平面ABC ,BC 平面ABC, 1 3 2 2 2 1
所以 p C2 .···········································································4分
(2,1) 3 2 3 3 9
所以平面ABC∥平面DEF .·····················································································6分
(备注:做出辅助线给1分;证明AB∥平面DEF给4分;证明平面ABC∥平面DEF给1分,过程酌情给分) (备注:求得p (2,0) 给2分;求得 p (2,1) 给2分)
(2)以 A 为坐标原点,分别以 AE , AF , AA 为 x,y,z 轴的正方向,建立空间直角坐标系,则 1 3 2 2 1
1 1 1 1 (2) p(X 2)C2 ,········································································6分
3 2 3 6
3 1 3 3 1 1
A 0,0, ,C , , ,D ,0,0,E ,0,0, 1
2 4 4 2 2 2
9 2
故 p(Y 1| X 2) .··················································································9分
1 3
1 3 1 3
所以AC , ,0,AD ,0, ,··························································8分 6
4 4 2 2
(备注:求得p(X 2)给2分;求得 p(Y 1/ X 2)给3分)
第 4 页 共 6 页(ii)证明:显然点A (1,0)为抛物线C 的焦点,∴|AT |a 14k2, ……………………11分 题号 题型 分值 考查的主要内容及知识点 难度
0 0 k k
易知|A A |4k2,且|AT |r 2 a 14k, 1 单选 5 指数不等式、集合交集运算 易
0 k k k k k
∴△A AT 为等腰三角形, 2 单选 5 复数的运算、复数的模 易
0 k k
1 3 单选 5 圆锥的表面积求解 易
易知△A AT 的面积S 4k (4k2)2 (2k)2 4k2 4k2 1, …………………………12分
0 k k k 2
4 单选 5 等比数列基本量求解 中
1 1 1
当k2时, 4k2 12 k2 4 2 k2 2 k2 2 k k , 5 单选 5 三角恒等变换、两角和、二倍角的正切公式 中
1 6 单选 5 幂函数性质、分段函数值域、根据常用逻辑用语求参 中
∴S 4k22(k )8(k3k), ………………………………………………………………14分
k k
7 单选 5 三角函数的图象与性质 中
1 1 1 1 1 1
∴ S 8(k3 k) 8k(k1)(k1) 16 k(k1) k(k1) , …………………………………16分 8 单选 5 利用导数研究函数性质 中难
k
9 多选 6 样本数据特征 易
n 1 1 n 1 1 1 1 1 1
∴ ,
k2 S k 16 k2 k(k 1) k(k 1) 162 n(n1) 32 10 多选 6 双曲线焦距、渐近线、焦点三角形 中
n 1 1 11 多选 6 以动点为载体,研究线面垂直、距离求解、体积定值问题 中难
∴不等式 得证. ………………………………………………………………………17分
S 32
k2 k 12 填空 5 二项式展开式 易
n 1 1 1 1 1
(备注:推导出三角形的面积公式给2分;利用放缩法构造裂项相消并求和,得出 < < 给
k2 S k 16 2 n(n1) 32 13 填空 5 投影向量、向量夹角 中
4分;下结论给1分,过程酌情给分)
14 填空 5 椭圆的第一定义、椭圆面积最值 中难
15 解答 13 解三角形、正弦定理、中点问题、三角形面积公式 易
16 解答 15 导数的几何意义、根据函数单调性求参数取值范围 中
17 解答 15 证明面面平行、求二面角的正弦值 中
18 解答 17 条件概率、分布列 中
19 解答 17 圆锥曲线新定义 难
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