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数学文科答案第1页,共4页2023年3月高中毕业班联合调研考试文科数学参考答案及评分标准一、选择题(每小题5分,共60分)1.B2.A3.C4.A5.C6.D7.C8.D9.B10.C11.C12.D二、填空题(
每小题5分,共20分)13.114.315.2316.6251,22三、解答题(共70分)17.(12分)解:(1)由题意知:��=45×0.1+55×0.15+65×0.2+75×0.3+85×0.15+95×0.1=70.5,....
..............5分∴这些参赛考生的竞赛平均成绩��为70.5..................................................................6分(2)由图可知,
90,100的考生占比100.0110%;80,100的考生占比100.0100.01525%,...................................................7分故进入复赛的分数线x在80~90之间
,且100.010900.01516%x,....10分解得86x,故进入复赛的分数线为86...............................................................12分18.(12分)解:(1)
证明:连接1BC,设11BCBCO,连接AO.11BCCB为菱形11BCBC,且11OBCBC为,的中点.....................................................
........2分11BCABBCABB又,11BCABC平面.............................4分11ACABC平面,11BCAC.............................................................
........................................6分(2)由(1)知111BCABCAOABC平面,又平面1BCAO,.............................7分又11,ACABOBC为的中点,112OABC由菱形111=
60BCCBCBB,°,2ABBC12,1,3BCOAOB222OAOBAB,OAOB................................................
...................................9分111,BCOBOOABCCB平面...............................................................................10分11
111123231333ABCCBBCCBVSOA.............................................................12分OA1AC1CB1B数学文科答案第2页,共4页19.(12分)
解:(1)设等比数列na的公比为q.由题意,可知11325114()3aaqaqaq..............................................................................................
...........2分解得113aq.......................................................................................................
.............4分11133nnna.....................................................................................................5分(2)由题设及(
1)可知:当n为奇数时,13nnnba,..................................................................................6分当n为偶数时,2113nnnnbbnann,.
..................................................7分故123,3,nnnnbnn为奇数为偶数,21234212nnnTbbbbbb…135
21242()()nnbbbbbbb……0242202422(3333)(33332462)nnn……….....8分024222(3333)(2462)nn
……..............................................9分213(22)2192nnn.................................
.....................................................11分91(1)4nnn..........................................................
...................................12分20.(12分)解:(1)当2a时,()2xfxe()0ln2()0ln2fxxfxx解,得;解,得,故(),ln2ln2,fx
在上单调递减,在上单调递增..................................4分(2)()xfxea0()0,()afxfxR当时,在上单调递增,此时()fx无两个零点;..................5分0()0,ln;()0,lnafxxafxxa
当时,解得解得,故(),lnln,fxaa在上单调递减,在上单调递增...................................7分xfxxfx
因为,;,故()fx有两不同零点,则min()ln0fxfa即2ln0aaae......................................................................................
..................9分数学文科答案第3页,共4页2()lngaaaae令则()1ln1lngaaa01()0,()agaga当时,单调递增,1()0,()agaga当时,单调递减
,........................................................................10分且2201()(1ln)0()agaaaege时,;又=02()0aega当时,..
..............................................................................................11分综上,a的范围为2.e,.................
.........................................................................12分21.(12分)解:(1)由题知,2p,∴C的方程为24yx........................................
..........................................................4分(2)抛物线2:4Cyx的焦点(1,0)F,设(2,)Pt,过P点的抛物线C的切线方程为:
2()xmyt,242()yxxmyt消去x得:244(2)0ymymt,①△21616(2)0mmt即220mtm,②.....................................................5分此时①可化为224
40ymym,解得2ym设直线1:2()PAxmyt,直线2:2()PBxmyt,则12,mm为方程②的两根,故12mmt,122mm,(*)..........................
......7分且122,2ABymym,可得211(,2)Amm,222(,2)Bmm,由②知,22112220,20mtmmtm,故20,2022AABBttxyxy,则直线AB方程为:202txy,显然0t则直线NF方程为:(1)2ty
x,故83(2,)(2,)2MNtt,,.............................................................................................9分83||||432tMNt,当且仅当
382tt时,2163t时取等号.此时,....................10分222222121222121212||()()()(22)()4()4ABABABxxyymmmmmmmmmm
由(*)得,221616470||44248333ABtt............12分数学文科答案第4页,共4页22.(10分)解:(1)曲线C1是以C1(4,0)为圆心的半圆,所以半圆的极坐标方程为�=8cos�(0≤�≤��
),.................................................3分曲线C2以C2(3,π2)为圆心的圆,转换为极坐标方程为�=2√3����(0≤�≤�).................................
.........................................................................................................
.5分(2)由(1)得:|��|=|��−��|=|8cos�3−2√3sin�3|=1..........................7分点2C到直线��的距离023sin302dOC.......................
.....................................9分所以�△����=12×|��|⋅�=12×1×√32=√34.................................................10分23.(12分
)(1)设�(�)=2|�−3|−|�|−1,则5,0()53,037,3xxfxxxxx≤≤................................................
.............................................2分()0033+.fx在-,单调递减,,单调递减,,单调递增min()(3)4.fxf=...............................................
.................................................4分要想2|�−3|−|�|−1≥�对任意的�∈R恒成立,只需min().mfx≤所以实数�的取值范围为
(−∞,−4];......................................5分(2)因为�∈(−∞,−4],所以t=m���=−4,即a2+b2+c2=16,.....................................
......................................................................6分(1a2+1+1�2+2+1�2+3)[(�2+1)+(�2+2)+(�2+3)]≥(���2�1×√�2+1+�1
�2�2×√�2+2+���2�3×√�2+3)�=9.............................8分当且仅当��2�11��2�1=��2�21��2�2=��2�31��2�3时取等号,即�=±√573,�=±√483,�=±
√393时取等号,而�2+�2+�2=16,所以有(1�2�1+1�2�2+1�2�3)×22≥9⇒1�2�1+1�2�2+1�2�3≥922................10分注:第17—23题提供的解法供
阅卷时评分参考,考生其它解法可相应给分。