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1邕衡金卷广西2023届高三一轮复习诊断性联考文科数学答案123456789101112DCCCBBDABDAA1.D【解析】1i,(1i)(1222i)123.zzz1i22616i36zzz
故选:D2.C3.C【解析】因为225Axyx,2250x,所以55Axx2412062Bxxxxx,则R6Bxxð或2x故R25ABxxð,故
选:C.4.C【解析】由几何体的三视图可知几何体的直观图如下:所以24432VSh.故选:C5.B【解析】2sin3fxx的图象关于直线3x对称,所以,332kkZ
,即13,2kkZ,当0k时,min12.6.B【解析】记2个“冰墩墩”为,ab,记3个“雪容融”为1,2,3,选取两个吉祥物作为冬奥会纪念品的基本事件有:,ab,,1a,,2a,,3a,
,1b,,2b,,3b,1,2,1,3,2,3,共10个。其中选取到1个“冰墩墩”和1个“雪容融”有6个基本事件,则概率为63105.7.D【解析】因为2(sin2)()22xxxxfxfx,所以fx是偶函数,故A,
C错误;2111sin2(1)022f,选项B符合函数fx,B不符合。故选:D.8.A【解析】∵函数e2xfxax,∴22e(2)ee(2)()(2)(2)xxxaxaaxafxaxax∴12e(2)(1)0(2)aafa,∴1a∴
22e(2)ee(1)()(2)(2)xxxxxfxxx2,x∴当2<1x时,()0fx,即函数fx在(2,1)上单调递减,当1x时,()0fx,即函数fx在(1,)上单调递增,2所以fx在1x处取得极小值即最小值,∴min(
)(1)fxf,∵函数e2xfxx在2,b上有最小值,∴1b,即1,b;故选:A.9.B【解析】设圆锥高为h,底面圆半径33hr,圆锥的体积为32111339hVhh
,圆柱的半径39hr,高为23h,体积为32212227381hVhh,所以12:2:9VV.10.D【解析】依题意可得0,因为0,x,所以,666x,要使函数在区间0,恰有三个极值点、三个零点,作出2si
nyt的图象,容易得到则5<326,解得819<36,即19,683.故选:D.11.A【解析】由题意得,点M为PQ中点12PQBFBFbkkkc22OMPQbkka,M(-4,1)22
4PQbbkca24bca22416bca,42161610ee2524e12.A【解析】方法一:构造法设()ln(1)(1)fxxxx,因为1()111xfxxx,当(1,0)x时,()0fx
,当,()0x时()0fx,所以函数()ln(1)fxxx在(0,)单调递减,在(1,0)上单调递增,所以()37(0)0ff,所以10n07l37,故37710lnl
n0.7,即ca,所以()(30)010ff,所以ln+1073010,故310e710,所以1303e1037,故bc,设()eln(1)(01)xgxxxx,则21e11()+1e11xxxgxxxx,令2(
)e(1)+1xhxx,2()e(21)xhxxx,当021x时,()0hx,函数2()e(1)+1xhxx单调递减,3当211x时,()0hx,函数2()e(1)+1x
hxx单调递增,又(0)0h,所以当021x时,()0hx,所以当021x时,()0gx,函数()eln(1)xgxxx单调递增,所以(0.3)(0)0gg,即0.30.3eln0.7,所以ba故选:A.方法二:比较法解:0.3ln(10.
3),0.0.310.33eabc,①lnln0.3ln(10.3)bc,令()ln(1),(0,0.3],fxxxx则1()1011xfxxx,故()fx在(0,0.3]上单调递减,可得(0.3)(0)0ff,即lnln0bc,所以bc;②0
.30.3ln(10.3)bae,令()ln(1),(0,0.3],xgxxexx则1111'11xxxxxegxxeexx,令()(1)(1)1xkxxxe,所以2()(12)0xkxxxe
,所以()kx在(0,0.3]上单调递增,可得()(0)0kxk,即()0gx,所以()gx在(0,0.3]上单调递增,可得(0.3)(0)0gg,即0ba,所以.ba故.abc13.1【解析
】由投影的定义知,a在b方向上的投影为12123cosa.14.315.2【解析】由题意得,四边形12PFQF是矩形,由焦点三角形面积公式得212tan1tan4512FPFb,11222FPFPFQFSS矩形.16.9364【解析】在ABC中,设A
Bc,BCa,ACb,由3ADDC,则1344BDBABC,则2221(93)16BDcaac,22216939caacac,即9256ac,49364433sin21
acacSABC,当且仅当ca3时取等号.所以ABC面积的最大值为9364.17.解:(1)根据表格可得男生观看人数为5+6+15+12+12+14+14+10+248=120....(2分)女生观看人数为4+6+7+17+11+13+13+8+8+13=10
0..............................(4分)所以可得列联表:观看没观看合计男生12080200女生100100200合计220180400..................(
6分)(表格数据对了,没有式子也可以得6分)(2)由题可得22400120100100804004.0403.84122018020020099K,(列出2K的表达式给2分,计算出40099给1分,计算出4.040给2分,与
3.841比较给1分)所以有95%的把握认为观看该影片与性别有关.(不回答或回答不标准扣1分)...(12分)18.解:(1)当1,n111112,,44Saa................
....................(1分)因为12.4nnSa①,当2n时,1112.4nnSa②,............................................(2分)①②
得,1122nnnnSSaa,.............................................(3分)即122nnnaaa,所以12nnaa,2n且N*n,所以na是以14为首项,2为公比的等比数列..
..............................(6分)(2)由(1)可得32nna,32log23nnbn................................(8分)全科试
题免费下载公众号《高中僧课堂》5所以2211515252222228nnnTnnnn,..........................(10分)所以,当2n或3n时,min3nT.............
.........................(12分)19.(1)延长DCABEI,连接ME交PB于F,连接FC,如图,四边形MFCD为截面.............................................(3分)(延长CD给1分,连
接ME给1分,截面1分.)ADE中,//BCAD,由12BCAD,则C为DE中点,B为AE中点...........(4分)过M作//MNAB交PB于N,则112MNAB,//MNAB.(5分
)12FNMNMNFEBFBFBE:2BFNF,即13BFBP.......................(6分)(2)ABCDMFEMADEFBCVVV............
............(7分)11633EMADADMVSAEg................................................(9分)118339EFBCFBECBFCVVSPAg..........................
..............(11分)409ABCDMFEMADEFBCVVV............................................(12分)20.解:(1)抛物线的准线为2px,当MD与x轴垂直时,点M的横坐标为p,此时=32
pMFp.........................................................(2分)所以2p.............................................
....................(3分)所以抛物线C的方程为24yx...............................................(4分)(2)设222231241234
,,,,,,,4444yyyyPyQyRySy,显然直线PQ的斜率不为0,...............................................
.(5分)设直线PQ:1xmy,与抛物线24yx联立可得2440ymy,且0则12.4yy................................................................(6分)6由P,B,R三点共线,
...................................................(7分)故BRPRkk,∴31322233114144yyyyyy即32313114yyyy,即13141yyy..........
.....(9分)同理:由Q,B,S三点共线,故BSQSkk,∴42222244414144yyyyyy即42424114yyyy,即24241yyy.............(10分)所以2314123142231421122222444444411
4444QRPSkkyyyyyyyyyyyyyyyyyy,所以直线QR与直线PS的斜率之和为定值-4..............................
.........(12分)21.解(1)当1a时,函数()(ln1)fxxx.()ln2fxx,...............(1分)则(1)2f,...........................
..................................(2分)即切线斜率为2,又(1)1f,...............................................(3分)则切线l的方程为12(1)
yx,即切线方程为210xy....................(4分)(2)∵12xx,是方程2()fxx的两个不等实根,212xx,且1>0x,20x,则2111122222ln0l
n0xxaxxxxaxx,即1122ln1ln1xaxxax,...................................(5分)∴12211221lnln2lnlnxxxxaxxxx,.......................
...................(6分)即21211221lnln2xxxxxxxx,................................................(7分)令21xtx,则2t,则12(
1)lnln21ttxxt,...................................................(8分)令(1)ln()1ttgtt,则212ln()(1)tttgtt
.......................................(9分)令1()2lnhtttt,则22(1)()0thtt,则()ht单调递增,∴3()(2)2ln202hth,即()0gt,则()gt单调递增,.........
...........(10分)7∴()(2)3ln2gtg,....................................................(11分)∴12ln23ln2xx,即1228ln3ln22lnexx,即1228exx...
................(12分)22.解:(Ⅰ)由sin3cos2yx(是参数)消去参数得:22143xy........(2分)将sin,cosyx代入上式..
........................................(3分)所以曲线C的极坐标方程为12sin4cos322(或22sin312)..(5分)(Ⅱ)∵点1(,)A,)32,(),3,(32
CB在在曲线C上,∴232221222111111OCOBOA.....................................(6分))]32(sin3)3(sin3s
in3[121222])cos23sin21(3)cos23sin21(3sin3[121222..........(7分)
22222cos43cossin23sin41cos43cossin23sin41sin9121(8分))cos23sin21sin9(121222.......................
................(9分)87239121........................................................(10分)23.解:(1)解法一
:由柯西不等式得:])()[(])()[())((24524524124125252121babababa.........................(3分)4)(])()[(])()[(22323245245241241bababa.
.............................(4分)当ab时,等号成立.所以原式得证........................................(5分)解法二:212525213325252121))((bababababa........
..........................(1分)232321252521223232)(babababa.........................................(2分)82323262622323
22)(bababa............................................(3分)当ab时,等号成立...........................................
..........(4分)即))((2525baba4)(22323ba....................................(5分)(2)解法一:由22323ba及2()4abab
.................................(6分)]3))[(()()(2212122121212121212121babababababa.................
(7分)]43)[()(22121221212121)(bababa4232121)(ba.................................................
...........(9分)当ab时,等号成立.所以2ba.........................................................(10分)解法二:因为22323
ba所以:)(4)(8)(23233212132121bababa................................(6分)2323232121234433babbaaba221212121212121
212121))((3))((3)(3)(3bababababababa.......(7分)又0,0ab,所以:0))((3221212121baba............
.....................................(8分)8)(32121ba当ab时,等号成立...................................(9分)所以,2ba........................
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