2018年考研数学三真题与解析.pdf
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1、2018年考研数学三真题及答案一、选择题1.下列函数中,在0 x处不可导的是().sinA fxxx.sinB fxxx.?C fxcos x.cosD fxx答案:D解析:方法一:000sin0limlimlimsin0,xxxxxxfxfxxxxA可导000sin0limlimlimsin0,xxxxxxfxfxxxxB可导20001cos102limlimlim0,xxxxxfxfxxCx可导0001cos102limlimlimxxxxxffxxxDx不存在,不可导应选D.方法二:因为,(1)0fcosxfx0001cos102limlimlimxxxxxfxfxxx不存在fx在0 x
2、处不可导,选D对:?Afxxsinx在0 x处可导对32:?Bfxxxxg在0 x处可导对():xxCfcos在0 x处可导.2.设函数fx在0,1 上二阶可导,且100,fx dx则10,02Afxf当时10,02Bfxf当时10,02Cfxf当时10,02Dfxf当时答案D【解析】将函数fx在12处展开可得2221110001111,222221111111,22222222ffxffxxffx dxffxxdxffxdx故当()0fx时,1011.0.22fx dxff从而有选D。3.设2222222211,1cos1xxxMdx Ndx Kx dxxe,则A.?.MNKB.MKNC.K
3、MND.KNM文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D
4、2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:
5、CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S
6、8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5
7、HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H
8、10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1
9、 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2答案:C解析:2222222221211,11xxMdxdxdxxx221xxNdxe,因为1xex所以11xxe221cos,1cos1.Kx dxx即
10、111cosxxxe所以由定积分的比较性质KMN,应选C.4.设某产品的成本函数C Q可导,其中Q为产量,若产量为0Q时平均成本最小,则()A00CQB00CQC QC.000CQQ C QD.000Q CQC Q答案D【解析】平均成本2,C QdC QCQ QC QC QQdQQ,由于C Q在0QQ处取最小值,可知000.Q CQ故选(D).5.下列矩阵中,与矩阵110011001相似的为111.011001A101.011001B111.010001C101.010001D文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5
11、HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H
12、10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1
13、 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7
14、J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D
15、2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:
16、CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S
17、8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2答案:A解析:令110010001P则1110010001P1110111110010011010001001001120110110011010011001001001PAPQ选项为A6.设,A B为n阶矩阵,记r X为矩阵X的秩,XY表示分块矩阵,则.?ArAABr A.?B r
18、ABArA.?,C rABmax r Ar B.?TTD r ABrA B答案:A解析:易知选项C错对于选项B举反例:取1 1001 112AB1 则001100,331133BAA BA7.设随机变量X的概率密度fx满足11fxfx,且200.6fx dx,则0_P X文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H
19、10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档
20、编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4
21、J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1
22、P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8
23、A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C
24、3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA
25、5M7J9H10D2文档编码:CB4J1S8Q1P5 HC8A8H10C3S1 ZA5M7J9H10D2(A)0.2;(B)0.3;(C)0.4;(D)0.6 解由11fxfx知,概率密度fx关于1x对称,故02P XP X,且00221P XPXP X,由于20020.6PXfx dx,所以200.4P X,即00.2P X,故选项 A 正确8.设12,nXXXK为取自于总体2,XN:的简单随机样本,令niiXnX11,2111()1niiSXXn,2211()niiSXXn,则下列选项正确的是_(A)n Xt nS:;(B)1n Xt nS:;(C)*n Xt nS:;(D)*1n Xt
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- 2018 考研 数学 三真题 解析
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