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2024 年秋季学期高一年级校联体第一次联考
数学参考答案
1.【答案】C
【详解】由全称命题的否定可知,命题“xR, x x2 1”的否定是“x R, x x2 1”.
0 0 0
故选:C.
2.【答案】B
【详解】因为B x|2x2 ,故AB1,1 ,故选:B.
3.【答案】C
1 x30
【详解】函数 f(x) x3 有意义,则 ,解得x3,
1x 1x0
所以原函数的定义域为[3,).
故选:C.
4.【答案】D
【详解】因为A0,1,所以集合A有,0,1,0,1共4个子集.
故选:D.
5.【答案】B
1x (1x)(1x)0
【详解】不等式 0等价于 ,解之得1x<1.
1x 1x0
故选:B.
6.【答案】A
【详解】 f x为奇函数可以推出 f 00,
但是 f 00推不出 f x为奇函数,
因此“ f 00”是“ f x是定义在R上的奇函数”的必要不充分条件.
故选:A.
7.【答案】A
m
【详解】因为 在,2 上单调递减,所以对称轴 2,即m4.
2
故选:A. ( )
8.【答案】B
【详解】解:由题意可知a0时,不等式显然不恒成立,
所以当a0,由不等式ax2xa0对所有的实数x都成立,
a0 1
可得 ,解得a .
0 2
故选:B.
9.【答案】AD
1
【详解】函数yx2是非奇非偶函数,yx 是(,0)(0,)上的奇函数,BC不是;
x
函数yx22,y x 1均为偶函数.又二次函数y x2 2在0,上为单调递增.
y x 1,当x0时,函数可化为yx1,在0,上为单调递增,AD正确.
故选:AD.
10.【答案】BC
【详解】对于A:若c0,则ac2 bc2 0,故A错误;
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{#{QQABaQCEggCoABAAAQgCQQliCEOQkhACAQgOwAAEMAAACBFABAA=}#}对于B:若ab4,则a2b2 2ab8,当且仅当ab2时,等号成立,故B正确;
对于C:若ab,cd ,则d c,所以ad bc,故C正确;
1 1
对于D:当b a 0时,则 ,故D错误.
b a
故选:BC.
11.【答案】ACD
【详解】对于A项,分式中分母不等于0,所以x10,解得:x1.
所以 f x的定义域是,1 1,;故A项正确;
对于B项,多个单调区间可用逗号(或“和”)隔开,所以 f x在,1,1,上单调递减,在
,1
1,上不是单调递减的,故B项错误;
2 2 2
对于C项, f x1 ,令g(x) ,定义域为(,0)(0,),g(x) g(x) 所以g(x)是奇函数,
x x x
即 f x1是奇函数,故C项正确;
对于D项, f x的值域是(,0)(0,),故D项正确.
故选:ACD.
12.【答案】1
【详解】 f 2 2 6 6 1 , f f 2 f 1 1 2 1.
2
故答案为:1.
13.【答案】 2
【详解】函数y x2 2x3的图象是开口向上,且以直线x 1 为对称轴的抛物线,
当x1,3时,y x2 2x3单调递增,在x1时取得最小值2.
故答案为:2.
14.【答案】6
ab 2 ab 2
【详解】a,b0,ab
,ab3
2 2
ab2 4(ab)120,
(ab)6 (ab)2 0,
ab60,ab6,当且仅当ab时,等式成立
即ab最小值为6
故答案为:6
15.【答案】(1)由Ax|x4,Bx|6x6得ABx|4 x6,················4分
ABx|x6 ······················································································4分(8分)
(2)由Bx|6x6得C B={x|x<-6或x>6},··········································2分
U
故A∩(C B)={x|x>6}···················································································3分(13分)
U
16.【答案】(1)∵x1,即x10,·······························································1分
1 1 1
4x 4x1 42 4x1 4448,·····························3分
x1 x1 x1
1 3
当且仅当 4x1,即 x 时取等号,··················································2分
x1 2
1
∴4x 的最小值为8.············································································1分(7分)
x1
(2)由题可得B是A的真子集,·······································································1分
当B,则m12m1m2;························································· 2分(10分)
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{#{QQABaQCEggCoABAAAQgCQQliCEOQkhACAQgOwAAEMAAACBFABAA=}#}2m17
当B,m≥2,则 (等号不同时成立),解得2m4;·············3分
m12
综上,m4.··························································································2分(15分)
17.【答案】(1)由题意作出函数图象如图所示.
············································································3分
x2 2x,x0
根据图象得函数f x ··················································.4分(7分)
x2 2x,x0
(2)由图可知,单调递减区间为,1,1,.················································· 4分(11分)
(3)由图可知,使 f x0的x的取值集合为x|0 x 2或x2 .·······················4分(15分)
18.【答案】(1)因为公司一年购买某种货物600吨,每次购买x吨,
600
所以购买货物的次数为 ,····································································1分
x
600 3600
故y 64x 4x260,x0,···················································5分
x x
化简得x265x9000,x0,解得20x45,··········································2分
所以x的取值范围为x|20x45 .···························································1分(9分)
3600
(2)由(1)可知y 4x,x0,······························································1分
x
3600 3600
因为 4x2 4x 240,··························································· 3分(13分)
x x
3600
当且仅当 4x即x30时等号成立,···················································2分
x
所以当x30时,一年的总费用最小,
故x的值为30.························································································2分(17分)
19.【答案】(1)令x y0可得: f(0) f(0) f(0),故 f(0)0,·························3分
(2)令yx可得: f(0) f(x) f(x),故 f(x)f(x) .···································3分
又函数 f(x)的定义域是R,
故函数 f(x)为奇函数.············································································1分(7分)
(3)先证明: f x在R上为增函数
证明:设任意x,x R,且x x ,则
1 2 1 2
f x 1 f x 2 f x 1 x 2 x 2 f x 2 f x 1 x 2 f x 2 f x 2 ····················3分
f x x
1 2
又当x0时, f x0,x x 0f x x 0,·····································1分
1 2 1 2
fxfx 0,f x f x ,···························································1分
1 2 1 2
即 f x在R上为增函数.···········································································1分(13分)
由(2)可知,函数 f(x)为R上的奇函数,
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{#{QQABaQCEggCoABAAAQgCQQliCEOQkhACAQgOwAAEMAAACBFABAA=}#}因为 f(x2) f x22x 0.
所以 f(x2)f x22x f 2xx2 .····················································1分
所以x22xx2,················································································1分
解得x1或x2,·················································································1分
故 x x1或x2 ··················································································1分(17分)
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{#{QQABaQCEggCoABAAAQgCQQliCEOQkhACAQgOwAAEMAAACBFABAA=}#}