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高三数学答案(第1页,共7页)2023年高考诊断性测试数学参考答案及评分标准一、选择题ACBBADBC二、选择题9.AC10.ACD11.ABD12.ABD三、填空题11.6012.437513.210xy
14.5,1485四、解答题17.解:(1)设数列na的公比为q,因为1323,,5aaa成等差数列,所以2111352aaqaq,························································
··············1分即2352qq,解得3q或12q,因为na各项均为正数,所以0q,所以3q.·····································2分由4355Sa,得412131
55331aa,解得11a.···························4分所以11133nnnaa.·····································································
····5分(2)由(1)知,13nnbn.··································································6分则01211323333nnTn所以12331323333nnTn
,···········································7分两式相减可得01123333nnnTn,·······································8分13313nnn
,整理可得211344nnnT.·······························································10分18.解:(1)因为2coscbAb,由正弦定理得sin2sincossinCBAB.···2分又πABC
,所以高三数学答案(第2页,共7页)ABBAABABABBsin()2sincossincoscossinsin()sin.····4分因为ABC为锐角三角形,所以AB22(0,),(0
,)ππ,AB22(,)ππ,又yxsin在22(,)ππ上单调递增,所以ABB,即AB2.···············6分(2)由(1)可知,AB2,所以在ABD中,ABCBAD,由正弦定理得:BBBADAB2)sin2πs
insin(2,所以BADBDcos1,所以BSABADBBBABD2cossintan1sin.····································9分又因为ABC为锐角三角形,所以B20π,B20
2π,B23π0π,解得B64ππ,···············································································11分所以B3tan(,1)3,即ABD面积的取值范
围为3(,1)3.·······················12分19.解:(1)Logistic非线性回归模型yuabt1e拟合效果更好.·····················1分从散点图看,散点更均匀地分布在该模型拟合曲线附近;
从残差图看,该模型下的残差更均匀地集中在以残差为0的直线为对称轴的水平带状区域内.····················3分(2)将yuabt1e两边取对数得yabtuln(1),···································5分则
ttbwwttiiiii()6650.208ˆ138.32()()1220120,b0.208ˆ,·····················7分awbt()1.6080.20810.50.576ˆˆ.················
····················9分高三数学答案(第3页,共7页)zyxEOABCDV所以y关于t的经验回归方程为0.5760.20812.51ety.··································10分当22t时,体长0.5760.208224
12.512.512.281e1eymm.·························12分20.解:(1)证明:取BC中点E,连接,,BDDEVE,因为ABCD为菱形,且60BAD
,所以BCD为等边三角形,故DEBC.····1分又在等边三角形VBC中,VEBC,·······2分DEVEE,所以BC面DEV.··········4分VD面DEV,所以BCVD;·············5分(2)由VEBC,DEBC,可得DE
V就是二面角ABCV的平面角,所以60DEV,··········································································6分在DEV中,3VEDE,所以DEV为边长为3的等边三角形,由(1)可知,面DEV
底面ABCD,取DE中点O,以O为坐标原点,以,,DAOEOV所在的方向为,,xyz轴的正向,建立空间直角坐标系Oxyz,····7分在VOE中,33,22OEOV,可得3(2,,0)2A,3(1,,0
)2B,3(1,,0)2C,3(0,0,)2V,故(2,0,0)CB,33(1,,)22CV,33(2,,)22AV.·········8分设(,,)xyzn为平面VBC的一个法向量,则有2033022xxyz,令3y,则1z,得(0,3,1
)n,·················10分设直线VA与平面VBC所成角为,则有||337sin|cos,|1427||||AVAVAVnnn,故直线VA与平面VBC所成角的正弦值为3714.·······················
···············12分高三数学答案(第4页,共7页)21.解:(1)设(,)Pxy,由题意||22|22|PFx,因为22||(2)PFxy,所以22(2)22|22|xyx,···················2分即222(2)|22|2xyx
,两边平方并整理得22142xy.故点P的轨迹C的方程为22142xy.··················································4分(2)设直线l方程为11(2)2ykxk≤≤,联立221421xyykx,消y并整理得,2
2(21)420kxkx,设1122(,),(,)AxyBxy,则122421kxxk,122221xxk,·············5分又121222()221yykxxk,可得线段AB中点坐标为2221(
,)2121kkk,所以线段AB中垂线的方程为22112()2121kyxkkk,令0y,可得2(,0)21kNk,··························································6分对于直线1ykx
,令0y,可得1(,0)Mk,所以22211||||21(21)kkMNkkkk.··················································7分高三数学答案(第5页,共7页)又22222122224821||1||1()8221212
1kkABkxxkkkkk,·············································································
·························9分所以2222||282628(1)14||11ABkkkMNkk,··························10分令251[,5]4tk,则22668(1)148141yktkt
,因为6814ytt在5[,5]4上单调递增,所以22[5,170]55y,故||44[5,170]||55ABMN.····························12分22.解:(1)21()c
os1(1)fxaxx,················································1分因为0为()fx的一个极值点,所以(0)20fa,所以2a.··········
···2分(2)①当10x时,()2110fx,所以()fx单减,所以对(1,0]x,有()(0)1fxf,此时函数()fx无零点;··········································3分当02x
时,32()2sin(1)fxxx,()fx在(0,)2上单调递减,又(0)20f,32()202(1)2f,由零点存在定理,存在0(0,)2x,使得()0fx,且当0(0
,)xx时,()0fx,即()fx单调递增,当0(,)2xx时,()0fx,即()fx单调递减.又因为(0)0f,所以0(0,]xx,()0fx,()fx在0(0,)x单增;因为高三数学答案(第6页,共7页)0()0fx,2
1()102(1)2f,所以存在10(,)2xx,当01(,)xxx时,()0fx,()fx单增,当1(,)2xx时,()0fx,()fx单减.所以,当1(0,)xx时,()fx单增,()(0)1fxf
;当1(,)2xx时,()fx单减,1()()202212fxf,此时()fx在(0,)2上无零点;···················5分当(,)2x时,21()2cos10(1)fxxx,所以()fx在(,)2单减,又()02f,
1()001f,由零点存在定理,函数()fx在(,)2上存在唯一零点;·································································
·······························6分当x时,1()2sin2101fxxxx,此时函数无零点;综上,()fx在区间(1,)上存在唯一零点.···········································7分
②因为21()2104(1)4f,由(1)中()fx在(0,)2上的单调性分析,知14x,所以()fx在(0,)4单增,所以对(0,)4x,有()(0)1fxf,即12sin11xxx,所以11si
n(1)21xxx.··································8分令21(2)xkk≥,则2222211111111sin()2111kkkkkkkk···9分所以22111111111sin()()(
)2334121nkknnn···················10分高三数学答案(第7页,共7页)因为xxsin,x4(0,]1,所以kkkkkk(1)1sin1111122,··········11分所以
knnnkn2231sin(1)()()11111111221,所以n2111kknsin1122.···························································
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