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高三年级第一次模拟考试数学试题参考答案第1页(共8页)吉林地区普通高中2023—2024学年度高三年级第一次模拟考试数学试题参考答案一、单项选择题:本大题共8小题,每小题5分,共40分.12345678ACBDACBC二、多项选择题:本
大题共4小题,共20分.全部选对的得5分,部分选对的得2分,有选错的得0分.三、填空题:本大题共4小题,每小题5分,共20分.其中第15题的第一个空填对得2分,第二个空填对得3分.13.514.5215.68;10816.)1,1(44ee(注:或写成1144
eme)7.教学建议:请教师们注意结合向量运算掌握三角形的“四心”问题.9.教学提示:建议教学中指导学生甄别a范围不同时,指、对函数的位置关系.(一)当1a时函数图象呈现以下三种情况图1图2图3如图2,当函数xay与xlogya有一个公共点)(00y,x在直线xy上,且在该公
共点处的切线为xy,所以有②①1000alnaxaxx,①代入②消0xa得eaalnalnxxx0010,,代入②中得exeae01即xay与xlogya的公共点为)(e
e,结合图象得到以下结论:(1)当eea1时,函数xay与xlogya的图象无公共点(如图1)(2)当eea1时,函数xay与xlogya的图象有一个公共点(如图2)(3)当eea11时,函数xay
与xlogya的图象有两个公共点(如图3)(二)当10a时函数图象呈现以下三种情况图4图5图6如图5,当函数xay与xlogya有一个公共点)(00y,x在直线xy上,且在该点处有公切线(斜率为1),所以有②①
1000alnaxaxx,①代入②消0xa得eaalnalnxxx11000,,代入②中得exeae10,即xay与xlogya的公共点为)11(ee,结合图象得到以下结论:(4)当eea0时,函数xay与xlogya
的图象有三个公共点(如图4)9101112BCDACDBCABD高三年级第一次模拟考试数学试题参考答案第2页(共8页)(5)当eea时,函数xay与xlogya的图象有一个公共点(如图5)(6)当1ae
e时,函数xay与xlogya的图象有一个公共点(如图6)15.教学建议:(1)关注《数学课程标准》中分层随机抽样的教学要求.(2)学生掌握推导过程.摘自《数学课程标准》:②分层随机抽样通过实例,了解分层随
机抽样的特点和适用范围,了解分层随机抽样的必要性,掌握各层样本量比例分配的方法.结合具体实例,掌握分层随机抽样的样本均值和样本方差.16.教学提示:当10xx且时,2)1()2()(xexxfx
,0)2(f当120xx且时,0)(xf;当2x时,0)(xf.故)(xf在)1,0(,)2,1(上单调递减,在),2(上单调递增,当2x时,)(xf取得极小值2)2(ef,当
1x时,)(xf;当1x时,)(xf;当x时,)(xf.由)(xf解析式可知,)(xf为奇函数.画出)(xf图象大致如下:令0)(xg得0)()(42exmfxf,设)(xft,
得关于t的方程)(042emtt0442em恒成立,设)(式有两个不等实根21,tt,当2221,etet时,即0m,满足题意,当22121ette或,12221etet满足题意,方法一:令42)(emttth,则
0)(0)1(0)(22ehheh或0)(0)1(0)(22ehheh故104em或014me综上,实数m的取值范围是)1,1(44ee.方法二:)(式化为tetm4,令)0()(4ttetth,易知)(thy在)
0(,,)0(,上单调递增,且41)1(eh,1)1(4eh,0)()(22eheh其图象大致如图:当104em或014me时,满足22121ette或
22211etet综上,实数m的取值范围是)1,1(44ee.四、解答题17.【解析】(Ⅰ)b//a032xcosxcosxsin··································
··························1分即0)3(xcosxsinxcos0xcos或33xtan····························································
····························3分)(0,x高三年级第一次模拟考试数学试题参考答案第3页(共8页)2x或6x·································································
··································5分(注:少一个解扣1分,没有角的范围表述扣1分.)方法二:b//a032xcosxcosxsin·························································1分02
21223xcosxsin21)6(2xsin··················································································
················3分)(0,x)611,6(62x662x或6562x6x或2x··························································
·········································5分(注:少一个解扣1分,没有角的范围表述扣1分.)(Ⅱ)21)(baxf2132xcosxcosxsin·······································
·········6分xcosxsin221223)6(2xsin·································································
·····················7分令kxk226222)(Zkkxk63··················································································
······9分)(xf的单调递增区间是)](63[Zkk,k·················································10分(注:单调区间没有写成区间形式扣1分,没有注明k的范围扣1分.)18.【解析】(Ⅰ)解:)0
(12)(xxxf·············································································1分所求切线斜率为1)1(f,切点为)2,1(··················
················································3分故所求切线方程为)1()2(xy,即01yx·················································5分(注
:将切线方程表示成1xy也给分)(Ⅱ)方法一:分离变量由xaxxf2)(2得2lnxxa在),0(恒成立···················································
········6分令)0(ln)(2xxxxg,则maxxga)(3ln21)(xxxg,0)(eg····························································
·····················8分当ex0时,0)(xg;当ex时,0)(xg故)(xg在),0(e上单调递增,在),(e上单调递减故当ex时,)(xg取最大值e21··············
·····························································11分故ea21,即a的取值范围是),21[e·················
·····················································12分(注:表示成ea21不扣分)高三年级第一次模拟考试数学试题参考答案第4页(共8页)方法二:分类讨论由xaxxf2)(2得0ln2xax在),0(恒成立·
···················································6分令)0(ln)(2xxaxxg,则xaxxaxxg1212)(2①当0a时,0)(xg恒成立,)(xg在),0(上单调递减,
0)1(ag又,故当1x时,0)(xg,不合题意;(或直接由02ln4)2(ag,不合题意或0)(,0ln,012xgxaxx时,当,不合题意)······················
·························8分②当0a时,axxg210)(得令,axxg210)(得令,axxg2100)(得令,故)(xg在)21,0(a上单调递减,)(xg在)
21(,a上单调递增故当ax21时,)(xg取最小值021ln21)21(aag·········································11分故ea21,即a的取值范围是),21[e综上所述,a的取值范围是),21[e···········
·······························································12分方法三:数形结合由xaxxf2)(2得xaxln2在),0(恒成立··································
·······················6分令xxhaxxgln)(,)(2,则当0x时,)()(xhxg恒成立xxhaxxg1)(,2)(若0a,)()(,0ln,012xhxgx
axx时,当,不合题意;·······························7分若0a,)()(xhxg曲线)(xgy与曲线)(xhy有且只有一个公共点,且在该公共点处的切线相同.设切点坐标
为),(00yx则00020012lnxaxxaxy解得eaex210故当ea21时,)()(xhxg即a的取值范围是),21[e.···························
··························································12分(教学建议:1.教师应强调第二问的法三比较适合选填题;2.在教学中,教师应注意强调)
0)(()(kkxlnxf的导函数的相关内容;变式:若xaxlnx,,x)1()21(]01[恒成立,求a的取值范围.19.【解析】(Ⅰ)选择①由已知可得:当1n时,221aS···················
·····································································1分当2n且Nn时,nnnnnaaSSa11高三年级第一次模拟考试数学试题参考答案第5
页(共8页)nnaa21即21nnaa·················································································
···········3分又112aa不符合上式Nnn,,n,ann且22121················································································
····5分选择②1nnaSnnnSSS1···········································································
··························1分nnSS21即21nnSS·············································································
·············3分又211aS}{nS是以2为首项,2为公比的等比数列.nnnS2221)(Nn····················································································5
分(Ⅱ)由(Ⅰ)可知nnnaS21,122nna121121)12)(12(2)1)(1(1121nnnnnnnnnaaSb···································9分nnbbbb
T321)121121()15171()7131()311(1nn12111n·······················································
··········································11分101211nnTNn························································
··············12分(注:若(Ⅰ)选择①,且未讨论1a的情况,扣2分;但若(Ⅱ)运算正确,(Ⅱ)问正常赋分.)关于劣构问题:劣构问题的常见形式:(1)目标界定不明确的结构不良问题;(2)具有多种解法、途径的结
构不良问题;(3)多个类似条件的结构不良问题;(4)问题条件或数据冗余的结构不良问题;(5)不同求解目标的结构不良问题.条件的选择原则:(1)应先分析所有条件,优先选择自己会做的、有把握的;(2)在有把握的前提下,优先选择难度最小的;(3)在选择条件时,要通盘考虑条件对整个
问题的影响.教学建议:(1)引导学生从知识的习得记忆转向问题的解决、策略的选择,使数学应用在思维层面真正发生;(2)注重渗透不良结构问题,采用开放式、互动式的教学方式,引导学生关注数学问题情境的变化;(3)注重变式训练,提高学生的辨析能力和应变能力.20.【解析】(
Ⅰ)设Q型芯片I级品该项指标的第70百分位数为a,则该指标在80以下的概率为55.0,该指标在90以下的概率为8.0,因此该项指标的第70百分位数为a一定在)90,80[内7.080025.010025.010023.010005.01
0002.0)(a(也可以用7.0190025.01002.0)(a)得86a高三年级第一次模拟考试数学试题参考答案第6页(共8页)所以Q型芯片I级品该项指标的第70百分位数为86························
······························3分(Ⅱ)当临界值65c时,Q型芯片Ⅱ级品应用于A型手机的概率为05.0657001.0)(····································6分(Ⅲ)设直接
将Q型芯片Ⅰ级品、Ⅱ级品应用于A型、B型手机时,该芯片生产商支出为y(万元),]6003010010[300]500050100020[700)()(c..c..yc5.5409]60,50[c·············
········································································8分所以当5650c时,101y,当56c时,101y,当6056c时,101y···················
··························································10分综上:为降低芯片生产商的成本,当临界值)56,50[c时,选择方案二;当临界值56c时,选
择方案一和方案二均可;当临界值]60,56(c时,选择方案一.······························································12分(注:以上三种情况,少一种扣1分,没有文字表述扣2分)21.【解析】(Ⅰ
)由正弦定理得AsinBsinAsinAcosCsin2)3(·································································1分AsinCAsinAsi
nAcosCsin2)()3(AsinCsinAcosCcossinAAsinAcosCsin2)3(即AsinCcossinACsinAsin230)(0,sinAA
2)6(2Csin即1)6(Csin··································································3分)67,6(6)(0,
CC26C3C··········································································································
······5分(注:没有角的范围表述扣1分.)(Ⅱ)方法一:BCAB,3CABC为等边三角形2ACBCAB(0,2),,2,mmBPxBExPECE在BPE中,由余弦定理得BcosBEBPBEBPPE2222···················
····················································7分即21)(22)(2222xmxmx整理可得(0,2),4422mmmmx
·········································································8分6346412)4(264124mmmmx当且仅当324
m时取等号即324BP时,CE取最小值634此时348BE································································································10
分.sinBEBPSPBE2431423)34(8)32(421321·················12分方法二:BCAB,3CABC为等边三角形高三年级第一次模拟考试数学试题参考答案第7页(共8页)2ACBCAB(0,2),2,
xxBExPECE设)32(0,,EPB在BPE中,由正弦定理得EPBsinBEEBPsinPE·················································································
·········7分即sinxsinx23整理可得)32(0,,233sinx························································
················8分当且仅当2时,x取最小值634当CE取最小值634时,348BE在BPEtR中,324216BEBP,BEP······························
···················10分.sinBEBPSPBE2431423)34(8)32(421321·················12分22.【解析】(Ⅰ)解:xcosmexfx)(···············
·································································1分方法一:函数)(xf在)0(,上单调递增0)(xcosmexfx在)0(,上恒成立(
且不恒为0)········································2分注:此处没取到等号,扣1分当20x时,0)(xf恒成立,即)(xf单调递增,0m当x2时,xcosemx恒成立设xcosexgx)(,xcosxsin
excosxsinxcosexgxx22)4(2)()(令0)(xg,则x43,令0)(xg,则432x)(xg在)432(,上单调递减,在)43(,上单调递增432)43()(egxgmin,
m432e又0m,m0432e综上,m的取值范围]20(43e,································································
········5分(注:(1)不写成区间形式也给分;(2)没写0m扣1分)方法二:函数)(xf在)0(,上单调递增0)(xcosmexfx在)0(,上恒成立(且不恒为0)又0m,xexcosm1在
)0(,上恒成立································································2分设xexcosxh)(xxexsinexcosxsinxh)4(2)(令0)(xh,
则x43,令0)(xh,则432x高三年级第一次模拟考试数学试题参考答案第8页(共8页))(xh在)432(,上单调递减,在)43(,上单调递增4322)43()(ehxhmin43221em又0m
,m0432e.综上,m的取值范围]20(43e,·················································································5分(Ⅱ)证
明:1m,xsinexfx)(,xcosexfx)(当0x时,1xe,1xcos,0)(xcosexfx)(xf在)0(,上单调递增,即)(xf在)0(,上无极值点·················
······················7分当0x时,设)()(xfxu,0)(xsinexux恒成立)(xu在)0(,上单调递增0)2(2eu,021122)43(4343
eeu由零点存在性定理,存在唯一一个)243(0,x,使得0)(0xu,即00xcosex当0xx时,0)(xu,0)(xf,)(xf在)(0x,
上单调递减当00xx时,0)(xu,0)(xf,)(xf在)0(0,x上单调递增)(xf在)(,上存在唯一极小值点0x·······························································10分(注
:此处0x所在区间必须是)243(,的子集,否则只给到10分位置))4(2)(000000xsinxsinxcosxsinexfx又)243(0,x,)43(40,x,)01()4(20,xsin即0
)(10xf······························································································
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