福州市3月质检数学理试题 扫描版含答案
福建省 高三数 3月质量检查试题 理(扫描版)

高三数学3月质量检查试题理(扫描版)2012年福州市高中毕业班质量检查 数学(理科)试卷参考答案及评分标准一、选择题(本大题共10小题,每小题5分,共50分.)1. A2. B3. D4. D5. C6. A7. C8. D9. B 10. C 二、填空题(本大题共5小题,每小题4分,共20分.) 11.30x y += 13. 18 14. ①②③ 15. 3、6、3三、解答题(本大题共6小题,共80分.) 16.(本小题满分13分)解:(Ⅰ)由已知得12n n a a +=,所以12n na a += 又12a =, 所以数列{}n a 是首项为2,公比为2的等比数列, ············ 3分 所以1*122()n n n a a n -=⋅=∈N . ····················· 5分 (Ⅱ)由(Ⅰ)知,2n n a =,所以2log ,n nb a n == ··········· 7分 所以11111(1)1n n b b n n n n +==-⋅⋅++, ··················· 10分 所以111111111223341n T n n ⎛⎫⎛⎫⎛⎫⎛⎫=-+-+-++- ⎪ ⎪ ⎪ ⎪+⎝⎭⎝⎭⎝⎭⎝⎭1111nn n =-=++. ······················· 13分 17.(本小题满分13分)解:(Ⅰ)∵X 的所有可能取值为0,1,2,3,4,(4,0.5)XB , ··· 1分∴40411(0)216P X C ⎛⎫=== ⎪⎝⎭,41411(1)24P X C ⎛⎫=== ⎪⎝⎭, 42413(2)28P X C ⎛⎫=== ⎪⎝⎭,43411(3)24P X C ⎛⎫=== ⎪⎝⎭, 44411(4)216P X C ⎛⎫=== ⎪⎝⎭, ···················· 6分X ∴的分布列为········· 7分(Ⅱ)Y 的所有可能取值为3,4,则 ·················· 8分1(3)(3)4P Y P X ====, ······················ 9分 3(4)1(3)4P Y P Y ==-==, ···················· 11分Y ∴的期望值1315()34444E Y =⨯+⨯=.答:Y 的期望值()E Y 等于154. ···················· 13分18.(本小题满分13分)解:(Ⅰ)依题意,得1b =. ····················· 1分∵c e a ==2221a c b -==,∴24a =. ·············· 3分 ∴椭圆的标准方程为2214x y +=. ··················· 4分(Ⅱ)(法一)证明:设()00,P x y ,00x ≠,则0(0,)Q y ,且220014x y +=. ∵M 为线段PQ 中点, ∴00,2x M y ⎛⎫⎪⎝⎭. ················ 5分又()0,1A ,∴直线AM 的方程为002(1)1y y x x -=+. 000,1,x y ≠∴≠令1y =-,得00,11x C y ⎛⎫- ⎪-⎝⎭. ···················· 8分又()0,1B -,N 为线段BC 的中点,∴00,12(1)x N y ⎛⎫- ⎪-⎝⎭. ········· 9分∴0000,122(1)x x NM y y ⎛⎫=-+ ⎪-⎝⎭. ···················10分 ∴22200000000000(1)222(1)44(1)x x x x x OM NM y y y y y y ⎛⎫⋅=-+⋅+=-++ ⎪--⎝⎭ =2220000000()1(1)044(1)x x y y y y y +-+=-++=-. ········ 12分 ∴OM MN ⊥. ··························· 13分(法二)同(法一)得: 00,2x M y ⎛⎫⎪⎝⎭,00,12(1)x N y ⎛⎫- ⎪-⎝⎭. ········· 9分当00y =时,02x =,此时()()()2,0,1,0,1,1P M N -,∴0OM k =,MN k 不存在,∴OM MN ⊥.······ 10分当00y ≠时,000022OM y y k x x ==, ()()()200000000000002111221221MNy y y x k x x x y x y y y y -------====---,∵1OM MN k k ⋅=-,∴OM MN ⊥ ···················· 12分 综上得OM MN ⊥. ························· 13分 19.(本小题满分14分) (Ⅰ)证明:∵ 菱形ABCD 的对角线互相垂直,∴BD AC ⊥,∴BD AO ⊥, ····················· 1分 ∵ EF AC ⊥,∴PO EF ⊥. ∵ 平面PEF ⊥平面ABFED ,平面PEF 平面ABFED EF =,且PO ⊂平面PEF ,∴ PO ⊥平面ABFED , ······················ 2分 ∵ BD ⊂平面ABFED ,∴ PO BD ⊥. ··························· 3分 ∵ AOPO O =,∴ BD ⊥平面POA . ························ 4分 (Ⅱ)如图,以O 为原点,建立空间直角坐标系O xyz -. ·········· 5分 (ⅰ)设.AO BD H =因为60DAB ∠=︒,所以BDC ∆为等边三角形, 故4BD =,2,HB HC ==又设PO x =,则OH x =,OA x =. 所以(0,0,0)O ,(0,0,)P x,,2,0)B x ,故,2,)PB OB OP x x =-=-, ·················· 6分所以(2PB=当x =min PB =此时PO =OH =·········· 7分 由(Ⅰ)知,PO ⊥平面,BFED所以221142)333P BFED BFED V S PO -=⋅⋅=⋅四棱锥梯形. ·····8分 (ⅱ)设点Q 的坐标为(),0,ac ,由(i)知,OPA,B ,2,0)D -,P . 所以()3,0,AQ a c =-,()QP a c =-, ··························· 9分∵AQ=QP λ,∴,a a c cλλ⎧--⎪⎨=-⎪⎩⇒a c ⎧=⎪⎪⎨⎪=⎪⎩.∴Q , ∴3(OQ =. (10)分 设平面PBD 的法向量为(,,)n x y z =,则0,0n PB n BD ⋅=⋅=.∵(3,2,PB =,()0,4,0BD =-,∴20,40y y +=-=⎪⎩,取1x =,解得:0,y =1z =, 所以(1,0,1)n =. ············· 11分 设直线OQ 与平面PBD 所成的角θ,∴sin cos ,OQ n OQ n OQ nθ⋅=<>===⋅== ········ 12分 又∵0λ>∴sin θ>. ······················· 13分 ∵[0,]2πθ∈,∴4πθ>.因此直线OQ 与平面PBD 所成的角大于4π,即结论成立. ········ 14分 20.(本小题满分13分)解:(Ⅰ)由已知可得ABC △为等边三角形. 因为CD AD ⊥,所以水下电缆的最短线路为CD .过D 作DE AB⊥于E ,可知地下电缆的最短线路为DE 、AB . ······· 3分又1,2CD DE AB ===, 故该方案的总费用为14220.5⨯+⨯5=+ …………6分(Ⅱ)因为0,3DCE πθθ⎛⎫∠=≤≤ ⎪⎝⎭所以1,tan ,tan cos CE EB ED AE θθθ====.·············· 7分 则)113sin 42tan 22cos cos cos y θθθθθ-=⨯+⨯+⨯=⨯+········ 9分令()3sin ,cos g θθθ-=则()()()222cos 3sin sin 3sin 1cos cos g θθθθθθθ-----'== , ···· 10分 因为03πθ≤≤,所以0sin θ≤≤, 记001sin ,(0,),33πθθ=∈当10sin 3θ≤<,即0≤0θθ<时,()0g θ'<,当1sin 3θ<≤0θ<θ≤3π时, ()0g θ'>, 所以()0min13()g g θθ-===y ≥, ·········· 12分此时0tan ED θ==,因此施工总费用的最小值为()万元,其中ED =··· 13分 21.(本小题满分7分) 选修4-2,矩阵与变换解:方程组可写为312423x y ⎛⎫⎛⎫⎛⎫= ⎪ ⎪ ⎪⎝⎭⎝⎭⎝⎭, ················· 2分系数行列式为32412⨯-⨯=,方程组有唯一解.利用矩阵求逆公式得11131242322-⎛⎫- ⎪⎛⎫=⎪ ⎪ ⎪⎝⎭- ⎪⎝⎭, ··············· 5分 因此原方程组的解为111222331222x y ⎛⎫⎛⎫- ⎪ ⎪⎛⎫⎛⎫== ⎪ ⎪ ⎪ ⎪ ⎪ ⎪⎝⎭⎝⎭- ⎪ ⎪⎝⎭⎝⎭,即1,21.2x y ⎧=⎪⎪⎨⎪=⎪⎩ ········ 7分(2)(本小题满分7分) 选修4-4:坐标系与参数方程 解:∵直线l 的极坐标方程为(cos sin )1ρθθ+=,∴直线l 的直角坐标方程为10x y +-=, ················ 2分又圆C 的普通方程为222(1)(1)x y r -+-=,所以圆心为(1,1),半径为r . ···················· 4分 因为圆心到直线l的距离d =, ··············· 6分 又因为直线l 与圆C相切,所以r =. ················ 7分 (3)(本小题满分7分)选修4-5:不等式选讲(法一)解:∵ a ,b ,R c ∈,2221a b c ++=,∴ 22222222()(111)()(111)3a b c a b c a b c ++=⋅+⋅+⋅≤++++=. ······ 5分当且仅当a b c ===时,a b c ++ ··········· 7分 (法二)解:∵222a b ab +≥,222b c bc +≥,222a c ac +≥ ∴ 2222()222a b c a b c ab bc ac ++=+++++222222222()()()a b c a b b c a c ≤+++++++++ ············· 3分∵ 2221a b c ++=,∴2()3a b c ++≤,当且仅当a b c ===时等号成立, ·········· 6分∴a b c ++ ······················ 7分。
2024届福建3月省质检数学试题答案

数学参考答案及评分细则 第1页(共 11页)2024届高中毕业班适应性练习卷数学参考答案及评分细则评分说明:1.本解答给出了一种或几种解法供参考,如果考生的解法与本解答不同,可根据试题的主要考查内容比照评分标准制定相应的评分细则.2.对计算题,当考生的解答在某一步出现错误时,如果后继部分的解答未改变该题的内容和难度,可视影响的程度决定后继部分的给分,但不得超过该部分正确解答应给分数的一半;如果后继部分的解答有较严重的错误,就不再给分.3.解答右端所注分数,表示考生正确做到这一步应得的累加分数. 4.只给整数分数.选择题和填空题不给中间分.一、选择题:本大题考查基础知识和基本运算.每小题5分,满分40分.1.B 2.D 3.A 4.C 5.A 6.C 7.B 8.B二、选择题:本大题考查基础知识和基本运算.每小题6分,满分18分.全部选对的得6分,部分选对的得部分分,有选错的得0分. 9.AD 10.ABD 11.BCD三、填空题:本大题考查基础知识和基本运算.每小题5分,满分15分.12.0.2718 13.56π;80π(仅答对一空给3分) 14四、解答题:本大题共5小题,共77分.解答应写出文字说明、证明过程或演算步骤.15.本小题主要考查正弦定理、余弦定理等基础知识,考查逻辑推理能力、运算求解能力等,考查化归与转化思想、函数与方程思想、数形结合思想等,考查数学运算、逻辑推理等核心素养,体现基础性和综合性.满分13分.解法一:(1)由πDAC BAC ∠+∠=,可得sin sin BAC DAC ∠=∠. ··············································· 1分 在ABC △中,由正弦定理,得sin sin AB BCC BAC=∠, ···························································· 3分所以sin sin BC CAB BAC=∠. 在ADC △中,由正弦定理,得sin sin AD CD C DAC=∠,··························································· 5分 所以sin sin CD CAD DAC=∠. 故AB BCAD CD=. ············································································································· 6分 因为D 为BC 的中点,所以2BCCD=,即2AB AD =. ································································ 7分 (2)由(1)不妨设AD x =,2AB x =,AC y =,BC =. ················································· 8分在ADC △中,由余弦定理,得cos C = ······················································ 9分在ABC △中,由余弦定理,得cos C = ················································ 10分= ···································································· 11分解得2232x y =. ·········································································································· 12分A D C B故cos C= ····································································· 13分解法二:(1)由πDAC BAC∠+∠=,得sin sinBAC DAC∠=∠. ················································· 1分因为D为BC的中点,所以2BCCD=,所以2ABCADCSS=△△. ···················································· 3分又因为1sin2ABCS AB AC BAC=⋅∠△, ········································································ 4分1sin2ADCS AD AC DAC=⋅∠△,················································································· 5分所以1sin221sin2AB AC BACAD AC DAC⋅∠=⋅∠, ················································································ 6分故2ABAD=.··········································································································· 7分(2)由(1)不妨设AD x=,2AB x=,AC y=,BC=.····································· 8分在ABD△中,由余弦定理,得cos ADB∠ ···································· 9分在ACD△中,由余弦定理,得cos ADC∠ ······································ 10分因为πADB ADC∠+∠=,所以cos cos0ADB ADC∠+∠=.+=,························································· 11分解得2232x y=. ···································································································· 12分故cos C=.··························································· 13分解法三:(1)设DACθ∠=.由πDAC BAC∠+∠=,得πBACθ∠=−,所以π2BADθ∠=−. ··········· 1分因为D为BC的中点,所以ABD ACDS S=△△, ······························································· 2分所以11sin(π2)sin22AB AD AC ADθθ⋅−=⋅, ······························································ 3分即sin2sinAB ACθθ=.因为sin22sin cosθθθ=,所以2cosAB ACθ=. ····························· 4分因为2AD AB AC=+,所以22242AD AB AC AB AC=++⋅ (5)分即22224||||4||cos4||(||cos)cos(π)AD AB AB AB ABθθθ=++⋅−.······································· 6分所以2||||AD AB=,即2ABAD=. ················································································ 7分(2)由(1)不妨设AD x=,2AB x=,AC y=,BC=.····································· 8分在ADC△中,由余弦定理,得cosθ=. ················································ 9分在ABC△中,由余弦定理,得cos(π)θ−10分AD CBθB CDA数学参考答案及评分细则第2页(共 11页)数学参考答案及评分细则 第3页(共 11页)所以cos cos(π)0θθ+−=+. ································· 11分 解得2232x y =. ···································································································· 12分故cos C=. ··························································· 13分 解法四:(1)取AB 中点E ,连结DE . ················································································ 1分又D 为BC 中点,所以DE AC ∥,··········································································· 2分 所以πBAC DEA ∠+∠=,DAC EDA ∠=∠. ································································· 4分 又πDAC BAC ∠+∠=,所以DAC DEA ∠=∠,故DEA EDA ∠=∠, ································· 5分所以AE AD =. ····································································································· 6分又2AB AE =,故2ABAD=. ······················································································ 7分 (2)不妨设AC y =,BC =.过A 作AF DE ⊥于点F ,过D 作DG AC ⊥于点G . ····················································· 8分又DE AC ∥,所以122yDE AC==,且AF AC ⊥, ······················································· 9分 所以四边形AFDG 为矩形.因为AE AD =,所以124y DF DE==. ······································································ 10分 所以4yAG DF ==,所以34y CG =. ········································································· 11分 又12CD BC ==,··························································································· 12分 所以cos CG C CD == ················································································· 13分 16.本小题主要考查递推数列、等差数列、等比数列及数列求和等基础知识,考查运算求解能力、逻辑推理能力等,考查化归与转化思想、分类与整合思想等,考查逻辑推理、数学运算等核心素养,体现基础性、综合性.满分15分.解法一:(1)因为2218n n a a n +−=,11a =,0n a >, 所以,当1n =时,22218a a −=,222189a a +,所以23a =. ····························································· 1分 当2n =时,223282a a −=×,22321625a a =+=,所以35a =. ··············································· 2分 当2n 时,22222222112211()()()n n n n n a a a a a a a a −−−=−+−++−+ ·················································· 3分8(1)8(2)811n n =−+−++×+ ························································································ 4分8[12(1)]1n +++−+(1)812n n −=×+······················································································· 5分 2(21)n −,··························································································· 6分 所以21na n =−.·········································································································· 7分 当1n =时,11a =也符合上式.综上,*21()n a n n =−∈N . ····························································································· 8分G F EB C D A数学参考答案及评分细则 第4页(共 11页)(2)由(1)得211421,2,n n n n b n −+− = 为奇数,为偶数,即221,2,nn n n b n − = 为奇数,为偶数.··············································· 9分 记1234561516S b b b b b b b b =++++ .则12378125292252292S =×+×+×++×+× ①, ·························································· 11分 2378921252212252292S = ×+×++×+×+× ②, ·············································· 12分①−②,得271238992(12)424242292242921281412S ×−−=1×2+×+×++×−×=+×−×=−− , ····························································································································· 14分 所以12814S = ,故123456151612814b b b b b b b b ++++=. ············································································ 15分 解法二:(1)因为2218n n a a n +−=,11a =,0n a >, 所以,当1n =时,22218a a −=,222189a a +,所以23a =. ····························································· 1分 当2n =时,223282a a −=×,22321625a a =+=,所以35a =. ··············································· 2分因为2218n n a a n +−=, 所以22221(21)(21)n n a a n n +−=+−−,即22221(21)(21)n n a n a n +−+=−−. ···································· 5分 所以2222211(21)(23)10n n a n a n a −−−=−−==−= ,即22(21)n a n =−. ···································· 7分 又0n a >,所以*21()n a n n =−∈N . ················································································· 8分 (2)由(1)得211421,2,n n n n b n −+− = 为奇数,为偶数,即221,2,n n n n b n − = 为奇数,为偶数. ··············································· 9分 记1234561516S b b b b b b b b =++++ .则12345678125292132172212252292S =×+×+×+×+×+×+×+× ···································· 11分22072208544134432007424=+++++++ ······························································ 14分12814=. 故123456151612814b b b b b b b b ++++=. ············································································ 15分 17.本小题主要考查条件概率、全概率公式、概率的分布列及期望等基础知识,考查数学建模能力、运算求解能力、逻辑推理能力等,考查统计与概率思想、分类与整合思想、函数与方程思想等,考查数学抽象、数学建模和数学运算等核心素养,体现应用性和创新性.满分15分. 解法一:(1)依题意,X 的所有可能取值为0,1,2. ································································ 1分设打成10:10后甲先发球为事件A ,则乙先发球为事件A ,且()()12PA P A ==, 所以()()()()()11111110002322236P X P A P X A P A P X A ==⋅=+⋅==××+××=, ···················· 2分()()()()()1112111112111123232223232P X P A P X A P A P X A ==⋅=+⋅==××+×+××+×= , ··· 3分()()()()()12111212222322233P X P A P X A P A P X A ==⋅=+⋅==××+××=. ························· 4分所以X 的分布列为故X 的均值为()11170126236E X =×+×+×=. ································································· 5分。
2019届福建省福州市高三3月质量检测数学(理)试题word版含解析

2019届福建省福州市高三3月质量检测数学(理)试题一、单选题1.已知复数满足,则在复平面内,对应的点位于( )A. 第一象限B. 第二象限C. 第三象限D. 第四象限【答案】B【解析】由题易得:∴对应的点为,在第二象限,故选:B2.为了解某地区的“微信健步走”活动情况,拟从该地区的人群中抽取部分人员进行调查,事先已了解到该地区老、中、青三个年龄段人员的“微信健步走”活动情况有较大差异,而男女“微信健步走”活动情况差异不大.在下面的抽样方法中,最合理的抽样方法是( ) A. 简单随机抽样 B. 按性别分层抽样C. 按年龄段分层抽样D. 系统抽样【答案】C【解析】我们常用的抽样方法有:简单随机抽样、分层抽样和系统抽样,事先已了解到该地区老、中、青三个年龄段人员的“微信健步走”活动情况有较大差异,而男女“微信健步走”活动情况差异不大. 了解某地区的“微信健步走”活动情况,,按年龄分层抽样,这种方式具有代表性,比较合理.故选:C.3.已知双曲线的两顶点间的距离为4,则的渐近线方程为( )A. B. C. D.【答案】B【解析】由双曲线的方程可知:,即,∴,解得:令,得到故选:B4.若角的顶点与原点重合,始边与轴的非负半轴重合,终边在直线上,则( )A. B. C. D.【答案】B【解析】由题意易得:,,故选:B5.已知三棱锥的四个顶点都在球的表面上,平面,,且,若平面截球所得截面的面积为,则球的表面积为( )A. B. C. D.【答案】D【解析】∵AB⊥BC,平面截球所得截面的面积为,∴AC为截面ABC的直径,AC=6,∴PC=,∵PA⊥平面ABC,∴PC的中点为球O的球心,∴球O的半径r==5,∴球O的面积S=4πr2=.故选:D.6.函数的图象大致为( )A. B. C. D.【答案】A【解析】的定义域为,为偶函数,排除C;当x时,,排除B,D故选:A点睛:识图常用的方法(1)定性分析法:通过对问题进行定性的分析,从而得出图象的上升(或下降)的趋势,利用这一特征分析解决问题;(2)定量计算法:通过定量的计算来分析解决问题;(3)函数模型法:由所提供的图象特征,联想相关函数模型,利用这一函数模型来分析解决问题.7.下面程序框图是为了求出满足的最大正整数的值,那么在和两个空白框中,可以分别填入( )A. “”和“输出”B. “”和“输出”C. “”和“输出”D. “”和“输出”【答案】D【解析】执行程序框图:,得到,判断不符合,∴“”排除A,B选项;,判断不符合,,判断不符合,,,判断符合,则“输出”故选:D点睛:本题主要考查程序框图的循环结构流程图,属于中档题. 解决程序框图问题时一定注意以下几点:(1) 不要混淆处理框和输入框;(2) 注意区分程序框图是条件分支结构还是循环结构;(3) 注意区分当型循环结构和直到型循环结构;(4) 处理循环结构的问题时一定要正确控制循环次数;(5) 要注意各个框的顺序,(6)在给出程序框图求解输出结果的试题中只要按照程序框图规定的运算方法逐次计算,直到达到输出条件即可.8.福州西湖公园花展期间,安排6位志愿者到4个展区提供服务,要求甲、乙两个展区各安排一个人,剩下两个展区各安排两个人,不同的安排方案共有( )A. 90种B. 180种C. 270种D. 360种【答案】B【解析】第一步,为甲地选一名志愿者,有=6种选法;第二步,为乙地选一名志愿者,有=5种选法;第三步,为剩下两个展区各安排两个人,有种选法.故不同的安排方案共有6×5×6=180种.故选:B.9.如图,网格纸上小正方形的边长为1,粗实线画出的是某几何体的三视图,则该几何体的体积为( )A. B. C. D.【答案】C【解析】由三视图可知,该几何体为组合体:上方为半个圆锥,下方为放倒的直四棱柱,∴该几何体的体积为:故选:C点睛:由三视图画出直观图的步骤和思考方法:1、首先看俯视图,根据俯视图画出几何体地面的直观图;2、观察正视图和侧视图找到几何体前、后、左、右的高度;3、画出整体,然后再根据三视图进行调整.10.设函数,则满足的的取值范围是( )A. B.C. D.【答案】C【解析】作出函数的图象,如图:等价于:或解得:或故选:C11.在平面直角坐标系中,抛物线的焦点为,准线为,过的直线交于两点,交于点,直线交于点.若,且.则( )A. 1B. 3C. 3或9D. 1或9【答案】D【解析】连接BD,易知:BD轴,G为准线与x轴的焦点,由抛物线的定义,|BF|=|BD|,|AF|=|AH|=3,∵,∴|BE|=2|BD|,∴∠BED=30°,故|AE|=2|AH|=6,∴,∴,交换A与B的位置,同理可得:故选:D12.已知函数的图象与直线恰有三个公共点,这三个点的横坐标从小到大分别为,则( )A. B. C. 0 D. 1【答案】B【解析】直线,即,直线过定点,函数的图象与直线恰有三个公共点即直线与的图象相切于B,C两点,,,,且∴∴∴.故答案为:B点睛:本题考查函数零点问题.函数零点问题有两种解决方法,一个是利用二分法求解,另一个是化原函数为两个函数,利用两个函数的交点来求解.本题采用第二种方法,充分利用函数的中心对称性及相切的关系布列方程即可.二、填空题13.已知集合,,则集合中元素的个数为____________.【答案】6【解析】∵,,∴,∴∴集合中元素的个数为6.故答案为:614.在钝角三角形中,,,,则面积为____________.【答案】或【解析】当∠B为钝角时,如图1,过点B作BD⊥AC,∵∠BAC=30°,∴BD=AB,∵AB=3,∴BD=,由勾股定理可得:AD==,∵BC=,∴由勾股定理得:CD==,∴AC=CD+AD=2,∴S=AC•BD=×2×=;△ABC当∠C为钝角时,如图2,过点B作BD⊥AC,交AC延长线于点D,∵∠BAC=30°,∴BD=AB,∵AB=3,∴BD=,∵BC=,∴由勾股定理得:CD==,AD==,∴AC=AD﹣DC=,=AC•BD=××=.∴S△ABC故答案为:或.15.设变量满足约束条件,则的取值范围为____________.【答案】【解析】作出可行域,如图所示:当直线经过B时取到最小值,没有最大值。
福州3月份质检理数(扫描版)

2015年福州市高中毕业班质量检测 理科数学能力测试参考答案及评分细则第Ⅰ卷 (选择题 共50分)一、选择题(本大题共10小题,每小题5分,共50分.)1. A 2. B 3. B 4. C 5. C 6.D 7.D 8. A 9. C 10. B第Ⅱ卷 (非选择题 共100分)二、填空题(本大题共5小题,每小题4分,共20分.)11.34i - 12.2 13.10x y +-=或10x y --= 14.3 15.①③④ 三、解答题(本大题共6小题,共80分.)16.本小题主要考查三角函数的图象与性质(对称性、周期性、单调性)、两角差的正弦公式、利用正弦定理解三角形等基础知识,考查运算求解能力,考查数形结合思想、化归与转化思想、函数与方程思想.满分13分. 解:(Ⅰ)因为()3sin cos (0,)f x x x x ωωω=->∈R ,所以π()2sin()6f x x ω=-. ·························································································· 1分所以函数()f x 的最大值为2. ····················································································· 2分 因为函数()f x 的图象与直线2y =的相邻两个交点之间的距离为π,所以πT =, ················································································································ 3分所以2ππω=,解得2,ω= ····························································································· 4分所以π()2sin(2).6f x x =-令πππ2π22π,262k x k k --+∈Z 剟,············································································· 5分 解得ππππ,63k x k k -+∈Z 剟.所以函数()f x 的单调递增区间是ππ[π,π],63k k k -+∈Z . ············································ 6分(Ⅱ)由(Ⅰ)知,π()2sin(2).6f x x =-在ABC ∆中,因为()2,f A =所以π2sin(2)2,6A -= ··································································································· 7分所以πsin(2)1,6A -=因为0πA <<,所以π3A =. ······················································································ 9分因为3a b =,根据据正弦定理,有sin 3sin A B =, ·············································· 10分所以πsin3sin 3B =,所以1sin 2B =, ······································································ 11分因为a b >,所以A B >,所以π03B <<, ······························································· 12分所以π6B =. ·············································································································· 13分17.本小题主要考查离散型随机变量的概率、分布列、数学期望等基础知识,考查数据处理能力、抽象概括能力、运算求解能力以及应用意识,考查必然与或然思想等.满分13分.解:(Ⅰ)设事件A 为“从10名被采访者中随机抽取两人,他们的职业满意度指标相同”. 职业满意度指标为0的有:9A ;职业满意度指标为1的有:2A ,4A ,5A ,7A ,10A ; 职业满意度指标为2的有:1A ,3A ,6A ,8A .从10名被采访者中随机抽取两人的所有可能结果数为210C , ····································· 1分45=, ········································ 2分职业满意度指标相同的所有可能结果数为2254C C + ····················································· 3分 106=+16=, ·································· 4分所以他们的职业满意度指标相同的概率16()45P A =. ·················································· 5分 (Ⅱ)计算10名被采访者的综合指标,可得下表:人员编号 1A 2A 3A4A 5A6A 7A 8A9A 10A综合指标4462453513其中成就感是一级的(4w ≥)有:1A 、2A 、3A 、5A 、6A 、8A ,共6名,成就感不是一级的(4w <)有4A 、7A 、9A 、10A ,共4名.随机变量X 的所有可能取值为:1,2,3,4,5. ····························································· 6分113211641(1)4C C P X C C ⋅===⋅, ··························································································· 7分1111312211647(2)24C C C C P X C C ⋅+⋅===⋅, ·········································································· 8分 11111131212111647(3)24C C C C C C P X C C ⋅+⋅+⋅===⋅ , ·························································· 9分 (4)P X ==111111211164C C C C C C ⋅+⋅⋅ 18=, ······································································· 10分 111111641(5)24C C P X C C ⋅===⋅, ······················································································ 11分所以X 的分布列为X 12345 p14 724 724 18124··································································································································· 12分所以1771129()123454242482412E X =⨯+⨯+⨯+⨯+⨯=. ···································· 13分 18.本小题主要考查空间体的直观图与三视图、直线与平面的平行、线面所成角、探索性问题等基础知识,考查空间想象能力、推理论证能力、运算求解能力,考查数形结合思想、化归与转化思想、函数与方程思想.满分13分. (Ⅰ)证明:(方法一)由三视图知,,,BA BP BC 两两垂直,故以B 为原点,,,BA BP BC 分别为x 轴,y 轴,z 轴正方向,建立如图所示的空间直角坐标系.…………………1分则1(0,2,0),(2,0,1),(1,1,),(2,1,0),(0,0,1)2P D M E C ,所以1=(1,0,)2EM -,易知平面ABCD 的一个法向量等于(0,1,0)n =,………3分 所以1=(1,0,)(0,1,0)02EM n ⋅-⋅=,所以EM n ⊥, ··········································································································· 4分 又EM ⊄平面ABCD ,所以EM ∥平面ABCD . ···························································································· 5分 (方法二)由三视图知,,,BA BP BC 两两垂直.连结,AC BD ,其交点记为O ,连结MO ,EM . ··············································· 1分 因为四边形ABCD 为矩形,所以O 为BD 中点.因为M 为PD 中点,所以OM ∥PB ,且12OM PB =.………………………2分又因为AE ∥PB ,且12AE PB =,所以AE ∥OM , 且AE =OM . 所以四边形AEMO 是平行四边形,所以EM ∥AO ………………………………………4分 因为EM ⊄平面ABCD ,AO ⊂平面ABCD所以EM ∥平面ABCD . ···························································································· 5分 (Ⅱ)解:当点N 与点D 重合时,直线BN 与平面PCD 所成角的正弦值为25. ······· 6分 理由如下:因为(2,2,1),(2,0,0)PD CD =-=,设平面PCD 的法向量为1111(,,)n x y z =,由110,0n PD n CD ⎧⋅=⎪⎨⋅=⎪⎩得1111220,20.x y z x -+=⎧⎨=⎩ ······································································· 7分 取11y =,得平面PCD 的一个法向量1(0,1,2)n =. ·················································· 8分 假设线段PD 上存在一点N ,使得直线BN 与平面PCD 所成角α的正弦值等于25. 设(01)PN PD λλ=≤≤,则(2,2,1)(2,2,)PN λλλλ=-=-,(2,22,)BN BP PN λλλ=+=-. ······················ 9分 所以111||sin |cos ,|||||BN n BN n BN n α⋅=<>=⋅ ································································ 10分222222255(2)(22)()5984λλλλλ===⋅+-+⋅-+. ······························ 12分 所以29810λλ--=, 解得1λ=或19λ=-(舍去). 因此,线段PD 上存在一点N ,当N 点与D 点重合时,直线BN 与平面PCD 所成角的正弦值等于25. 13分 19.本小题主要考查椭圆的标准方程与性质、直线与椭圆的位置关系、推理与证明等基础知识,考查推理论证能力、运算求解能力,考查化归与转化思想、数形结合思想等.满分13分.解:(Ⅰ)设椭圆Γ的半焦距为c ,依题意,得2221,23,.c a a c b a c ⎧=⎪⎪⎨+=⎪⎪=-⎩ ········································· 2分解得22,3.a b =⎧⎪⎨=⎪⎩················································································································· 3分所以椭圆Γ的方程为22143x y +=.··············································································· 4分(Ⅱ)方法一:依题意得, PQ 与坐标轴不垂直.设()()1122,,,P x y Q x y .因为点Q 与点Q '关于x 轴对称,所以()22,Q x y '-.由(Ⅰ)讨论可知,()()2,0,1,0A F -. 因为PF AQ '∥,所以直线FQ 与直线AQ '的斜率相等,故222212y y x x -=+-, ··············· 6分 解得212x =. ··············································································································· 7分 又因为点()22,Q x y 在椭圆Γ上,所以2354y =,或2354y =-.······························ 8分由椭圆对称性,不妨取2354y =,则直线PQ 的斜率22512y k x ==+. 所以直线PQ 方程为()512y x =+. ··········································································· 9分 由()2251,23412,y x x y ⎧=+⎪⎨⎪+=⎩得点P 坐标为735,48⎛⎫-- ⎪ ⎪⎝⎭. ························································ 10分 所以()()()()()2222222211111811111164PF x y x k x k x =++=+++=++=, ··················· 11分 ()()()()()2222222222222812221216AQ x y x k x k x '=-+=-+-=+-=. ····················· 12分所以12PF AQ '=. ··································································································· 13分方法二:依题意,得PQ 与坐标轴不垂直.设l 方程为()1y k x =+(0k ≠),()()1122,,,Px y Qx y .因为点Q 与点Q '关于x 轴对称,所以()22,Q x y '-.又因为椭圆关于x 轴对称,所以点Q '也在椭圆Γ上.由()221,3412,y k x x y ⎧=+⎨+=⎩消去y 得 ()22223484120k x k x k +++-=. ································· 5分 所以2212122284120,,3434k k x x x x k k-∆>+=-⋅=++. ·························································· 6分因为PF AQ '∥,所以直线AQ '的方程为()2y k x =-.由()222,3412,y k x x y ⎧=-⎨+=⎩消去y 得()2222341616120k x k x k +-+-=. ································· 7分 因为直线AQ '交椭圆于()()222,0,,A Q x y '-两点,所以2221612234k x k -⋅=+,故2228634k x k -=+. ····································································· 8分所以22221211212222868864120,,34343434k k k k x x x x x x k k k k ---∆>+=+=-⋅=⋅=++++, 解得2157,44k x ==-. ·································································································· 9分所以222861342k x k -==+. ······························································································ 10分 所以()()()()()2222222211111811111164PF x y x k x k x =++=+++=++=,()()()()()2222222222222812221216AQ x y x k x k x '=-+=-+-=+-=. ····················· 12分所以12PF AQ '=. ··································································································· 13分方法三:依题意,得PQ 与坐标轴不垂直.设l 方程为()1y k x =+(0k ≠),()()1122,,,Px y Qx y .因为点Q 与点Q '关于x 轴对称,所以()22,Q x y '-. 又因为椭圆关于x 轴对称,所以点Q '也在椭圆Γ上.直线PQ '过定点()4,0M -, ························································································· 5分 理由如下:由()221,3412,y k x x y ⎧=+⎨+=⎩消去y 得()22223484120k x k x k +++-=. ···································· 6分 所以2212122284120,,3434k k x x x x k k -∆>+=-=++.····························································· 7分 所以()()()21122112121222411234kx y x y x k x x k x kx x k x x k-+=⋅++⋅+=++=+, ()()()1212122611234ky y k x k x k x x k k +=+++=++=+. ············································· 9分 因为()()11224,,4,MP x y MQ x y '=+=+-,所以()()()()211221121222242444403434k kx y x y x y x y y y k k-+++=+++=+=++, ·········· 11分 所以MP MQ '∥,所以,,M P Q '三点共线,即直线PQ '过定点()4,0M -. ················· 12分因为F 为线段AM 中点,PF AQ '∥,所以12PF AQ '=. ··································································································· 13分方法四:依题意,得PQ 与坐标轴不垂直. 设l 方程为()1y k x =+(0k ≠),()()1122,,,Px y Qx y .因为点Q 与点Q '关于x 轴对称,所以()22,Q x y '-. ······················································ 5分 因为,,P F Q 三点共线,所以()111,FP x y =+与()221,FQ x y =+共线,所以()()1221110x y x y +-+=. ··················································································· 6分 因为PF AQ '∥,所以可设FP AQ λ'=(0λ>),即()()11221,2,x y x y λ+=--,所以()121212,x x y y λλ+=-=-. ················································································ 7分。
2025届福建福州市高三3月学情调研数学试题试卷

2025届福建福州市高三3月学情调研数学试题试卷请考生注意:1.请用2B 铅笔将选择题答案涂填在答题纸相应位置上,请用0.5毫米及以上黑色字迹的钢笔或签字笔将主观题的答案写在答题纸相应的答题区内。
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一、选择题:本题共12小题,每小题5分,共60分。
在每小题给出的四个选项中,只有一项是符合题目要求的。
1.设数列{}()*n a n N ∈的各项均为正数,前n 项和为nS,212log 1log n n a a +=+,且34a =,则6S =( )A .128B .65C .64D .632.已知函数()2ln e x f x x =,若关于x 的方程21[()]()08f x mf x -+=有4个不同的实数根,则实数m 的取值范围为( ) A .3(0,)4B .2(0,)2C .23(,)24D .2(,1)23.已知集合M ={x |﹣1<x <2},N ={x |x (x +3)≤0},则M ∩N =( ) A .[﹣3,2)B .(﹣3,2)C .(﹣1,0]D .(﹣1,0)4.已知ABC ∆中内角,,A B C 所对应的边依次为,,a b c ,若2=1,7,3a b c C π+==,则ABC ∆的面积为( )A .332B .3C .33D .235.已知,a R b R ∈∈,则“直线210ax y +-=与直线(1)210a x ay +-+=垂直”是“3a =”的( ) A .充分不必要条件 B .必要不充分条件 C .充要条件D .既不充分也不必要条件6.已知函数()f x 是R 上的偶函数,且当[)0,x ∈+∞时,函数()f x 是单调递减函数,则()2log 5f ,31log 5f ⎛⎫ ⎪⎝⎭,()5log 3f 的大小关系是( )A .()()3521log log 3log 55f f f <<⎛⎫⎪⎝⎭B .()()3251log log 5log 35f f f <<⎛⎫⎪⎝⎭C .()()5321log 3log log 55f f f ⎪<⎛⎫⎝⎭< D .()()2351log 5log log 35f f f ⎪<⎛⎫⎝⎭< 7.若,则( ) A .B .C .D .8.执行如图所示的程序框图,若输出的结果为3,则可输入的实数x 值的个数为( )A .1B .2C .3D .49.设等比数列{}n a 的前项和为n S ,若2019201680a a +=,则63S S 的值为( )A .32B .12C .78 D .9810.下列四个图象可能是函数35log |1|1x y x +=+图象的是( )A .B .C .D .11.已知复数z 满足32i z i ⋅=+(i 是虚数单位),则z =( ) A .23i +B .23i -C . 23i -+D . 23i --12.设过定点(0,2)M 的直线l 与椭圆C :2212x y +=交于不同的两点P ,Q ,若原点O 在以PQ 为直径的圆的外部,则直线l 的斜率k 的取值范围为( )A .65,⎛- ⎝⎭B .665,,53⎛⎛ ⎝⎭⎝C .652⎛⎝ D .665,,522⎛⎛-⎝⎭⎝二、填空题:本题共4小题,每小题5分,共20分。
2020届福建省高三下学期3月质量检测数学(理)试卷及答案

2020届福建省高三下学期3月质量检测数学(理)试卷★祝考试顺利★本试卷共5页。
满分150分。
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一、选择题:本题共12小题,每小题5分,共60分。
在每小题给出的四个选项中,只有一项是符合题目要求的。
1.已知集合A={x|x≥1},B={x|(x-4)(x+2)≥0},则Rð(AUB)=A.{x|-2≤x≤1}B.{x|1≤x≤4}C.{x|-2<x<1}D.{x|x<4}2.等差数列{an }的前n项和为Sn,若a4=4,S13=104,则a10=A.10B.12C.16D.203.设x,y满足约束条件2010x yx yy-≥-≤-≤⎧⎪⎨⎪⎩,则z=2x+y的最大值是A.0B.3C.4D.54.(2x-1)(x+2)5的展开式中,x3的系数是A.200B.120C.80D.405.某市为了解居民用水情况,通过抽样得到部分家庭月均用水量的数据,制得频率分布直方图(如图)。
若以频率代替概率,从该市随机抽取5个家庭,则月均用水量在8~12吨的家庭个数X的数学期望是A.3.6B.3C.1.6D.1.56.在△ABC 中,2DC BD =u u u r u u u r ,且E 为AC 的中点,则DE u u u r = A.2136AB AC +u u u r u u u r - B.2136AB AC -u u u r u u u r C.1136AB AC -u u u r u u u r - D.2536AB AC +u u u r u u u r 7.若双曲线上存在四点,使得以这四点为顶点的四边形是菱形,则该双曲线的离心率的取值范围是 232,+∞3+∞)8.某学生到工厂实践,欲将一个底面半径为2,高为3的实心圆锥体工件切割成一个圆柱体,并使圆柱体的一个底面落在圆锥体的底面内。
福建省福州市高二数学下学期3月月考试卷理(含解析)

福建省福州市高二数学下学期3月月考试卷理(含解析)一.选择题:本大题共12小题,每小题5分,在每小题给出的四个选项中,只有一个是符合题目要求的1.一个物体的运动方程为s=1﹣t+t2其中s的单位是米,t的单位是秒,那么物体在3秒末的瞬时速度是()A.7米/秒B.6米/秒C.5米/秒D.8米/秒2.若f'(x)=3,则等于()A.3 B.C.﹣1 D.13.若曲线y=x2+ax+b在点(1,b)处的切线方程是x﹣y+1=0,则()A.a=1,b=2 B.a=﹣1,b=2 C.a=1,b=﹣2 D.a=﹣1,b=﹣24.设f(x)=xlnx,若f′(x0)=2,则x0=()A.e2B.e C. D.ln25.下列积分不正确的是()A.B.C. D.6.已知函数f(x)=x3+ax2+(a+6)x+1有极值,则a的取值范围是()A.﹣1<a<2 B.﹣3<a<6 C.a<﹣3或a>6 D.a<﹣1或a>27.设P为曲线C:y=x2+2x+3上的点,且曲线C在点P处切线倾斜角的取值范围是,则点P横坐标的取值范围是()A.B.[﹣1,0] C.[0,1] D.[,1]8.若函数f(x)=x3+ax﹣2在区间(1,+∞)内是增函数,则实数a的取值范围是()A.[﹣3,+∞)B.(﹣3,+∞)C.[0,+∞)D.(0,+∞)9.设曲线在点(3,2)处的切线与直线ax+y+1=0垂直,则a=()A.2 B.C.D.﹣210.曲线y=ln(2x﹣1)上的点到直线2x﹣y+8=0的最短距离是()A.B.2 C.3 D.011.设f(x)、g(x)分别是定义在R上的奇函数和偶函数,当x<0时,f′(x)g(x)+f(x)g′(x)>0,且g(﹣3)=0,则不等式f(x)g(x)<0的解集是()A.(﹣3,0)∪(3,+∞)B.(﹣3,0)∪(0,3)C.(﹣∞,﹣3)∪(3,+∞)D.(﹣∞,﹣3)∪(0,3)12.已知二次函数f(x)=ax2+bx+c的导数为f′(x),f′(0)>0,对于任意实数x,有的最小值为()A.2 B.C.3 D.二、填空题:共4小题,每小题5分,共20分.13.函数y=x2﹣lnx的单调递减区间为.14.已知函数f(x)=f′()sinx+cosx,则f()= .15.由y2=4x与直线y=2x﹣4所围成图形的面积为.16.已知函数f(x)的定义域为[﹣1,5],部分对应值如表,f(x)的导函数y=f′(x)的图象如图示.x ﹣1 0 4 5 f(x) 1 2 2 1下列关于f(x)的命题:①函数f(x)的极大值点为0,4;②函数f(x)在[0,2]上是减函数;③如果当x∈[﹣1,t]时,f(x)的最大值是2,那么t的最大值为4;④当1<a<2时,函数y=f(x)﹣a有4个零点;⑤函数y=f(x)﹣a的零点个数可能为0、1、2、3、4个.其中正确命题的序号是.三、解答题:共6小题,共70分,解答写出文字说明、证明过程或演算步骤.17.已知等差数列{a n}满足a3=6,a4+a6=20(1)求通项a n;(2)设{b n﹣a n}是首项为1,公比为3的等比数列,求数列{b n}的通项公式及其前n项和T n.18.在三角形ABC中,∠A、∠B、∠C的对边分别为a、b、c,若bcosC=(2a﹣c)cosB (Ⅰ)求∠B的大小(Ⅱ)若、a+c=4,求三角形ABC的面积.19.已知椭圆=1(a>b>0)的一个顶点为A(0,1),离心率为,过点B(0,﹣2)及左焦点F1的直线交椭圆于C,D两点,右焦点设为F2.(1)求椭圆的方程;(2)求△CDF2的面积.20.设f(x)=ax3+bx2+cx的极小值为﹣8,其导函数y=f′(x)的图象经过点,如图所示,(1)求f(x)的解析式;(2)若对x∈[﹣3,3]都有f(x)≥m2﹣14m恒成立,求实数m的取值范围.21.已知函数f(x)=ln(ax+1)+,x≥0,其中a>0.(Ⅰ)若f(x)在x=1处取得极值,求a的值;(Ⅱ)求f(x)的单调区间;(Ⅲ)若f(x)的最小值为1,求a的取值范围.22.已知函数,g(x)=x+lnx,其中a>0.(1)若x=1是函数h(x)=f(x)+g(x)的极值点,求实数a的值;(2)若对任意的x1,x2∈[1,e](e为自然对数的底数)都有f(x1)≥g(x2)成立,求实数a的取值范围.2016-2017学年福建省福州市文博中学高二(下)3月月考数学试卷(理科)参考答案与试题解析一.选择题:本大题共12小题,每小题5分,在每小题给出的四个选项中,只有一个是符合题目要求的1.一个物体的运动方程为s=1﹣t+t2其中s的单位是米,t的单位是秒,那么物体在3秒末的瞬时速度是()A.7米/秒B.6米/秒C.5米/秒D.8米/秒【考点】62:导数的几何意义.【分析】求导数,把t=3代入求得导数值即可.【解答】解:∵s=1﹣t+t2,∴s′=﹣1+2t,把t=3代入上式可得s′=﹣1+2×3=5由导数的意义可知物体在3秒末的瞬时速度是5米/秒,故选C2.若f'(x)=3,则等于()A.3 B.C.﹣1 D.1【考点】6F:极限及其运算.【分析】由=﹣=﹣×f'(x0),由题意,即可求得答案.【解答】解:=﹣=﹣×f'(x0)=﹣×3=﹣1,故选C.3.若曲线y=x2+ax+b在点(1,b)处的切线方程是x﹣y+1=0,则()A.a=1,b=2 B.a=﹣1,b=2 C.a=1,b=﹣2 D.a=﹣1,b=﹣2【考点】6H:利用导数研究曲线上某点切线方程.【分析】由y=x2+ax+b,知y′=2x+a,再由曲线y=x2+ax+b在点(1,b)处的切线方程为x ﹣y+1=0,求出a和b.【解答】解:∵y=x2+ax+b,∴y′=2x+a,∵y′|x=1=2+a,∴曲线y=x2+ax+b在点(1,b)处的切线方程为y﹣b=(2+a)(x﹣1),∵曲线y=x2+ax+b在点(1,b)处的切线方程为x﹣y+1=0,∴a=﹣1,b=2.故选B.4.设f(x)=xlnx,若f′(x0)=2,则x0=()A.e2B.e C. D.ln2【考点】65:导数的乘法与除法法则.【分析】利用乘积的运算法则求出函数的导数,求出f'(x0)=2解方程即可.【解答】解:∵f(x)=xlnx∴∵f′(x0)=2∴lnx0+1=2∴x0=e,故选B.5.下列积分不正确的是()A.B.C. D.【考点】68:微积分基本定理.【分析】利用微积分基本定理即可得出.【解答】解:A. = =ln3,因此正确;B.∵=2.故B不正确.==,因此正确;D. = = =.因此正确.综上可知:只有B不正确.故选B.6.已知函数f(x)=x3+ax2+(a+6)x+1有极值,则a的取值范围是()A.﹣1<a<2 B.﹣3<a<6 C.a<﹣3或a>6 D.a<﹣1或a>2【考点】6D:利用导数研究函数的极值.【分析】求出函数的导数,利用导数有两个不相等的实数根,通过△>0,即可求出a的范围.【解答】解:函数f(x)=x3+ax2+(a+6)x+1,所以函数f′(x)=3x2+2ax+(a+6),因为函数有极值,所以导函数有两个不相等的实数根,即△>0,(2a)2﹣4×3×(a+6)>0,解得:a<﹣3或a>6,故选:C.7.设P为曲线C:y=x2+2x+3上的点,且曲线C在点P处切线倾斜角的取值范围是,则点P横坐标的取值范围是()A.B.[﹣1,0] C.[0,1] D.[,1]【考点】62:导数的几何意义.【分析】根据题意知,倾斜角的取值范围,可以得到曲线C在点P处斜率的取值范围,进而得到点P横坐标的取值范围.【解答】解:设点P的横坐标为x0,∵y=x2+2x+3,∴y′=2x0+2,利用导数的几何意义得2x0+2=tanα(α为点P处切线的倾斜角),又∵,∴0≤2x0+2≤1,∴.故选:A.8.若函数f(x)=x3+ax﹣2在区间(1,+∞)内是增函数,则实数a的取值范围是()A.[﹣3,+∞)B.(﹣3,+∞)C.[0,+∞)D.(0,+∞)【考点】6A:函数的单调性与导数的关系.【分析】由已知,f′(x)=3x2≥0在[1,+∞)上恒成立,可以利用参数分离的方法求出参数a的取值范围.【解答】解:f′(x)=3x2+a,根据函数导数与函数的单调性之间的关系,f′(x)≥0在[1,+∞)上恒成立,即a≥﹣3x2,恒成立,只需a大于﹣3x2的最大值即可,而﹣3x2在[1,+∞)上的最大值为﹣3,所以a≥﹣3.即数a的取值范围是[﹣3,+∞).故选A.9.设曲线在点(3,2)处的切线与直线ax+y+1=0垂直,则a=()A.2 B.C.D.﹣2【考点】62:导数的几何意义.【分析】(1)求出已知函数y在点(3,2)处的斜率;(2)利用两条直线互相垂直,斜率之间的关系k1•k2=﹣1,求出未知数a.【解答】解:∵y=∴y′=﹣∵x=3∴y′=﹣即切线斜率为﹣∵切线与直线ax+y+1=0垂直∴直线ax+y+1=0的斜率为﹣a.∴﹣•(﹣a)=﹣1得a=﹣2故选D.10.曲线y=ln(2x﹣1)上的点到直线2x﹣y+8=0的最短距离是()A.B.2 C.3 D.0【考点】6H:利用导数研究曲线上某点切线方程;3H:函数的最值及其几何意义;IT:点到直线的距离公式.【分析】在曲线y=ln(2x﹣1)上设出一点,然后求出该点处的导数值,由该导数值等于直线2x﹣y+8=0的斜率求出点的坐标,然后由点到直线的距离公式求解.【解答】解:设曲线y=ln(2x﹣1)上的一点是P( m,n),则过P的切线必与直线2x﹣y+8=0平行.由,所以切线的斜率.解得m=1,n=ln(2﹣1)=0.即P(1,0)到直线的最短距离是d=.故选B.11.设f(x)、g(x)分别是定义在R上的奇函数和偶函数,当x<0时,f′(x)g(x)+f(x)g′(x)>0,且g(﹣3)=0,则不等式f(x)g(x)<0的解集是()A.(﹣3,0)∪(3,+∞)B.(﹣3,0)∪(0,3)C.(﹣∞,﹣3)∪(3,+∞)D.(﹣∞,﹣3)∪(0,3)【考点】6B:利用导数研究函数的单调性.【分析】先根据f’(x)g(x)+f(x)g’(x)>0可确定[f(x)g(x)]'>0,进而可得到f(x)g(x)在x<0时递增,结合函数f(x)与g(x)的奇偶性可确定f(x)g(x)在x>0时也是增函数,最后根据g(﹣3)=0可求得答案.【解答】解:设F(x)=f (x)g(x),当x<0时,∵F′(x)=f′(x)g(x)+f (x)g′(x)>0.∴F(x)在当x<0时为增函数.∵F(﹣x)=f (﹣x)g (﹣x)=﹣f (x)•g (x)=﹣F(x).故F(x)为(﹣∞,0)∪(0,+∞)上的奇函数.∴F(x)在(0,+∞)上亦为增函数.已知g(﹣3)=0,必有F(﹣3)=F(3)=0.构造如图的F(x)的图象,可知F(x)<0的解集为x∈(﹣∞,﹣3)∪(0,3).故选D12.已知二次函数f(x)=ax2+bx+c的导数为f′(x),f′(0)>0,对于任意实数x,有的最小值为()A.2 B.C.3 D.【考点】63:导数的运算;3R:函数恒成立问题;7F:基本不等式.【分析】由对于任意实数x,f(x)≥0成立求出a的范围及a,b c的关系,求出f(1)及f′(0),作比后放缩去掉c,通分后利用基本不等式求最值.【解答】解:∵f(x)≥0,知,∴c.又f′(x)=2ax+b,∴f′(0)=b>0,f(1)=a+b+c.∴≥1+=≥1+=2.当且仅当4a2=b2时,“=”成立.故选A.二、填空题:共4小题,每小题5分,共20分.13.函数y=x2﹣lnx的单调递减区间为(0,1] .【考点】6B:利用导数研究函数的单调性.【分析】根据题意,先求函数的定义域,进而求得其导数,即y′=x﹣=,令其导数小于等于0,可得≤0,结合函数的定义域,解可得答案.【解答】解:对于函数,易得其定义域为{x|x>0},y′=x﹣=,令≤0,又由x>0,则≤0⇔x2﹣1≤0,且x>0;解可得0<x≤1,即函数的单调递减区间为(0,1],故答案为(0,1]14.已知函数f(x)=f′()sinx+cosx,则f()= 0 .【考点】63:导数的运算.【分析】求函数的导数,先求出f′()的值即可得到结论.【解答】解:函数的导数为f′(x)=f′()cosx﹣sinx,令x=,得f′()=f′()cos﹣sin=﹣1,则f(x)=﹣sinx+cosx,则f()=﹣sin+cos=,故答案为:0.15.由y2=4x与直线y=2x﹣4所围成图形的面积为9 .【考点】67:定积分.【分析】先联立方程,组成方程组,求得交点坐标,可得被积区间,再用定积分表示出曲线yy2=4x与直线y=2x﹣4所围成的封闭图形的面积,即可求得结论【解答】解:联立方程组,解得或,∴曲线y=x2与直线y=x围成的封闭图形的面积为S=(y+2﹣y2)dy=(y2+2y﹣)|=9,故答案为:916.已知函数f(x)的定义域为[﹣1,5],部分对应值如表,f(x)的导函数y=f′(x)的图象如图示.x ﹣1 0 4 5 f(x) 1 2 2 1下列关于f(x)的命题:①函数f(x)的极大值点为0,4;②函数f(x)在[0,2]上是减函数;③如果当x∈[﹣1,t]时,f(x)的最大值是2,那么t的最大值为4;④当1<a<2时,函数y=f(x)﹣a有4个零点;⑤函数y=f(x)﹣a的零点个数可能为0、1、2、3、4个.其中正确命题的序号是①②⑤.【考点】6E:利用导数求闭区间上函数的最值;6D:利用导数研究函数的极值.【分析】由导数图象可知,函数的单调性,从而可得函数的极值,故可得①,②正确;因为在当x=0和x=4,函数取得极大值f(0)=2,f(4)=2,要使当x∈[﹣1,t]函数f(x)的最大值是4,当2≤t≤5,所以t的最大值为5,所以③不正确;由f(x)=a知,因为极小值f(2)未知,所以无法判断函数y=f(x)﹣a有几个零点,所以④不正确,根据函数的单调性和极值,做出函数的图象如图,即可求得结论.【解答】解:由导数图象可知,当﹣1<x<0或2<x<4时,f'(x)>0,函数单调递增,当0<x<2或4<x<5,f'(x)<0,函数单调递减,当x=0和x=4,函数取得极大值f(0)=2,f(4)=2,当x=2时,函数取得极小值f(2),所以①正确;②正确;因为在当x=0和x=4,函数取得极大值f(0)=2,f(4)=2,要使当x∈[﹣1,t]函数f(x)的最大值是4,当2≤t≤5,所以t的最大值为5,所以③不正确;由f(x)=a知,因为极小值f(2)未知,所以无法判断函数y=f(x)﹣a有几个零点,所以④不正确,根据函数的单调性和极值,做出函数的图象如图,(线段只代表单调性),根据题意函数的极小值不确定,分f(2)<1或1≤f(2)<2两种情况,由图象知,函数y=f(x)和y=a的交点个数有0,1,2,3,4等不同情形,所以⑤正确,综上正确的命题序号为①②⑤.故答案为:①②⑤.三、解答题:共6小题,共70分,解答写出文字说明、证明过程或演算步骤.17.已知等差数列{a n}满足a3=6,a4+a6=20(1)求通项a n;(2)设{b n﹣a n}是首项为1,公比为3的等比数列,求数列{b n}的通项公式及其前n项和T n.【考点】8E:数列的求和.【分析】(1)由已知条件,利用等差数列的通项公式列出方程组,求出等差数列的首项和公差,由此能求出等差数列的通项公式.(2)由a n=2n,{b n﹣a n}是首项为1,公比为3的等比数列,利用等比数列的通项公式,能求出数列{b n}的通项公式,再利用分组求和法能求出数列{b n}的前n项和T n.【解答】解:(1)∵等差数列{a n}满足a3=6,a4+a6=20,∴,解得,∴.(2)∵a n=2n,{b n﹣a n}是首项为1,公比为3的等比数列,∴,∴,∴.18.在三角形ABC中,∠A、∠B、∠C的对边分别为a、b、c,若bcosC=(2a﹣c)cosB (Ⅰ)求∠B的大小(Ⅱ)若、a+c=4,求三角形ABC的面积.【考点】HR:余弦定理;HP:正弦定理.【分析】(Ⅰ)根据正弦定理得: ===2R解出a、b、c代入到已知条件中,利用两角和的正弦函数的公式及三角形的内角和定理化简,得到cosB的值,然后利用特殊角的三角函数值求出B即可;(Ⅱ)要求三角形的面积,由三角形的面积公式S=acsinB知道就是要求ac的积及sinB,由前一问的cosA的值利用同角三角函数间的基本关系求出sinA,可根据余弦定理及、a+c=4可得到ac的值,即可求出三角形的面积.【解答】解(Ⅰ)由已知及正弦定理可得sinBcosC=2sinAcosB﹣cosBsinC∴2sinAcosB=sinBcosC+cosBsinC=sin(B+C)又在三角形ABC中,sin(B+C)=sinA≠0∴2sinAcosB=sinA,即,得(Ⅱ)∵b2=7=a2+c2﹣2accosB∴7=a2+c2﹣ac又∵(a+c)2=16=a2+c2+2ac∴ac=3∴即19.已知椭圆=1(a>b>0)的一个顶点为A(0,1),离心率为,过点B(0,﹣2)及左焦点F1的直线交椭圆于C,D两点,右焦点设为F2.(1)求椭圆的方程;(2)求△CDF2的面积.【考点】K4:椭圆的简单性质.【分析】(1)根据椭圆的基本概念和平方关系,建立关于a、b、c的方程,解出a=,b=c=1,从而得到椭圆的方程;(2)求出F1B直线的斜率得直线F1B的方程为y=﹣2x﹣2,与椭圆方程联解并结合根与系数的关系算出|x1﹣x2|=,结合弦长公式可得|CD|=,最后利用点到直线的距离公式求出F2到直线BF1的距离d,即可得到△CDF2的面积.【解答】解:(1)∵椭圆=1(a>b>0)的一个顶点为A(0,1),离心率为,∴b==1,且=,解之得a=,c=1可得椭圆的方程为;…(2)∵左焦点F1(﹣1,0),B(0,﹣2),得F1B直线的斜率为﹣2∴直线F1B的方程为y=﹣2x﹣2由,化简得9x2+16x+6=0.∵△=162﹣4×9×6=40>0,∴直线与椭圆有两个公共点,设为C(x1,y1),D(x2,y2),则∴|CD|=|x1﹣x2|=•=•=又∵点F2到直线BF1的距离d==,∴△CDF2的面积为S=|CD|×d=×=.20.设f(x)=ax3+bx2+cx的极小值为﹣8,其导函数y=f′(x)的图象经过点,如图所示,(1)求f(x)的解析式;(2)若对x∈[﹣3,3]都有f(x)≥m2﹣14m恒成立,求实数m的取值范围.【考点】6D:利用导数研究函数的极值;36:函数解析式的求解及常用方法;3R:函数恒成立问题.【分析】(1)求出y=f'(x),因为导函数图象经过(﹣2,0)和(,0),代入即可求出a、b、c之间的关系式,再根据图象可知函数的单调性,而f(x)极小值为﹣8可得f(﹣2)=﹣8,解出即可得到a、b、c的值;(2)根据函数增减性求出函数在区间[﹣3,3]的最小值大于等于m2﹣14m,即可求出m的范围.【解答】解:(1)∵f'(x)=3ax2+2bx+c,且y=f'(x)的图象经过点(﹣2,0),,∴∴f(x)=ax3+2ax2﹣4ax,由图象可知函数y=f(x)在(﹣∞,﹣2)上单调递减,在上单调递增,在上单调递减,由f(x)极小值=f(﹣2)=a(﹣2)3+2a(﹣2)2﹣4a(﹣2)=﹣8,解得a=﹣1∴f(x)=﹣x3﹣2x2+4x(2)要使对x∈[﹣3,3]都有f(x)≥m2﹣14m恒成立,只需f(x)min≥m2﹣14m即可.由(1)可知函数y=f(x)在[﹣3,﹣2)上单调递减,在上单调递增,在上单调递减且f(﹣2)=﹣8,f(3)=﹣33﹣2×32+4×3=﹣33<﹣8∴f(x)min=f(3)=﹣33﹣33≥m2﹣14m⇒3≤m≤11故所求的实数m的取值范围为{m|3≤m≤11}.21.已知函数f(x)=ln(ax+1)+,x≥0,其中a>0.(Ⅰ)若f(x)在x=1处取得极值,求a的值;(Ⅱ)求f(x)的单调区间;(Ⅲ)若f(x)的最小值为1,求a的取值范围.【考点】6D:利用导数研究函数的极值;6B:利用导数研究函数的单调性;6E:利用导数求闭区间上函数的最值.【分析】(Ⅰ)对函数求导,令f′(1)=0,即可解出a值.(Ⅱ)f′(x)>0,对a的取值范围进行讨论,分类解出单调区间.a≥2时,在区间(0,+∞)上是增函数,(Ⅲ)由(2)的结论根据单调性确定出最小值,当a≥2时,由(II)知,f(x)的最小值为f(0)=1,恒成立;当0<a<2时,判断知最小值小于1,此时a无解.当0<a<2时,(x)的单调减区间为,单调增区间为【解答】解:(Ⅰ),∵f′(x)在x=1处取得极值,f′(1)=0即 a+a﹣2=0,解得 a=1(Ⅱ),∵x≥0,a>0,∴ax+1>0①当a≥2时,在区间(0,+∞)上f′(x)>0.∴f(x)的单调增区间为(0,+∞)②当0<a<2时,由f′(x)>0解得由∴f(x)的单调减区间为,单调增区间为(Ⅲ)当a≥2时,由(II)知,f(x)的最小值为f(0)=1当0<a<2时,由(II)②知,处取得最小值,综上可知,若f(x)的最小值为1,则a的取值范围是[2,+∞)22.已知函数,g(x)=x+lnx,其中a>0.(1)若x=1是函数h(x)=f(x)+g(x)的极值点,求实数a的值;(2)若对任意的x1,x2∈[1,e](e为自然对数的底数)都有f(x1)≥g(x2)成立,求实数a的取值范围.【考点】6D:利用导数研究函数的极值;6B:利用导数研究函数的单调性;6E:利用导数求闭区间上函数的最值.【分析】(1)通过、x=1是函数h(x)的极值点及a>0,可得,再检验即可;(2)通过分析已知条件等价于对任意的x1,x2∈[1,e]都有[f(x)]min≥[g(x)]max.结合当x∈[1,e]时及可知[g(x)]max=g(e)=e+1.利用,且x∈[1,e],a>0,分0<a<1、1≤a≤e、a>e三种情况讨论即可.【解答】解:(1)∵,g(x)=x+lnx,∴,其定义域为(0,+∞),∴.∵x=1是函数h(x)的极值点,∴h′(1)=0,即3﹣a2=0.∵a>0,∴.经检验当时,x=1是函数h(x)的极值点,∴;(2)对任意的x1,x2∈[1,e]都有f(x1)≥g(x2)成立等价于对任意的x1,x2∈[1,e]都有[f(x)]min≥[g(x)]max.当x∈[1,e]时,.∴函数g(x)=x+lnx在[1,e]上是增函数.∴[g(x)]max=g(e)=e+1.∵,且x∈[1,e],a>0.①当0<a<1且x∈[1,e]时,,∴函数在[1,e]上是增函数,∴.由1+a2≥e+1,得a≥,又0<a<1,∴a不合题意;②当1≤a≤e时,若1≤x<a,则,若a<x≤e,则.∴函数在[1,a)上是减函数,在(a,e]上是增函数.∴[f(x)]min=f(a)=2a.由2a≥e+1,得a≥,又1≤a≤e,∴≤a≤e;③当a>e且x∈[1,e]时,,∴函数在[1,e]上是减函数.∴.由≥e+1,得a≥,又a>e,∴a>e;综上所述:a的取值范围为.。
福建省福州市2019届高三毕业班3月质检数学理

2019年福州市高中毕业班质量检测理科数学试卷(完卷时间:120分钟;满分:150分)第I卷(选择题共50分)一、选择题:本大题共10小题•每小题5分,共50分.在每小题给出的四个选项中,只有一项是符合题目要求的•1•已知集合A={( x,y)|y=lgx}, B={(x,y)|x=a},若A A B= 一,则实数a的取值范围是( ).A. a<1B. a< 1C. a<0D. a< 02•“实数a=1 ”是“复数(1 ai)i ( a€ R ,i为虚数单位)的模为2 ”的().A.充分非必要条件B.必要非充分条件3.4.5. C.充要条件执行如图所示的程序框图D.既不是充分条件又不是必要条件,输出的M的值是( )开始J 」—►M=2―►i=1A . 2B. -11c.—命题” x R,使得f (x )二xA. _X R,都有f (x)二XC. —x R,都有f (x) = x是i<5?否”的否定是B.不存在x -D. x R,使输出MR,使f (x) x已知等比数列{a n}的前n项积为二n,若a3 d a8A.512B.256C.81i=i+1M 二结束).D.166.如图,设向量OA = (3,1),OB =(13),若OC =入OA +卩OB,且入》卩> 1,则用阴影表示C点所9.若定义在R 上的函数f(x)满足f(-x)=f(x), f(2- x)=f(x), 且当x € [0,1]时,其图象是四分之一圆(如图所示),则函数A. f(x)=x+sinxB. f (x ) =cos x xC.f(x)=xcosx兀3兀D.f (x )= x(--)(-云)8.已知F i 、22x yF 2是双曲线—22 " (a>0,b>0)的左、右焦点a b,若双曲线左支上存在一点 P 与点F 2关于直线y =■ bx对称”则该双曲线的离心为().a、5A.-2B. 5C.2D.2H(x)= |xej —f(x)在区间[—3,1]上的零点个数为()3210.已知函数f (x )=x +bx+cx+d (b 、c 、d 为常数),当x € (0,1)时取得极大值,当x € (1,2)时取极小值,则1 2 2(b -) (c- 3)的取值范围是().2nH x(-1) sin 2n,x [2n,2n 1)9f(x)二-2,(n N)n ' :1z x(-1)n 1sin 2n 2,x [2 n 1,2 n 2)I. 2若数列{a m }满足 a m = f (m )(m N ),且的前 m 项和为 S m ,则 S 2014 - S 2006 = _____________2三、解答题:本大题共六个小题,共80分.解答应写出文字说明、证明过程和演算步骤.A •(旦,5)B. .5,5)2C. (37,25)4D.(5,25)第H 卷(非选择题共100分)二、填空题:本大题共5小题,每小题4分,共20分. 11.5名同学排成一列,某个同学不排排头的排法种数为(用数字作答)12.如图所示,在边长为1的正方形OABC 中任取一点 M ,则点M 恰好取自 阴影部分的概率为 ____________ .2 213.若直线 x - y • 2 =0 与圆 C: (x -3) • (y -3) =4 相交于 A 、两点,则CA CB 的值14.已知某几何体的三视图(单位:cm )如图所示,则该几何体的表面积为15.已知函数A.5B.4C.3D.216. (本小题满分13分)在对某渔业产品的质量调研中,从甲、乙两地出产的该产品中各随机抽取10件,测量该产品中某种元素的含量(单位:毫克).下表是测量数据的茎叶图:甲地乙地8 01 2 4 7 8 8 92 0 0 1 2(优质品件数/总件数);规定:当产品中的此种元素含量羽5毫克时为优质品(I )试用上述样本数据估计甲、乙两地该产品的优质品率(n )从乙地抽出的上述10件产品中,随机抽取3件,求抽到的3件产品中优质品数■的分布列及数学期望E().17. (本小题满分13分)已知函数f (x) = 2cos2x 2、3sin xcosx(x R)..(I)当[0,—]时,求函数f(x)的单调递增区间;2(n)设ABC的内角A,B,C的对应边分别为a,b,c,且c = 3, f(C)=2,若向量m=(1,sinA)与向量n = (2,sinB)共线,求a,b 的值.18. (本小题满分13分)如图,直角梯形ABCD中,.ABC =90°AB = BC二2AD=4,点E、F分别是AB、CD的中点,点G在EF上,沿EF将梯形AEFD翻折,使平面AEFD丄平面EBCF .(I)当AG+ GC最小时,求证:BD丄CG ;(n)当2V B- ADGE = V D-GBCF时,求二面角D- BG- C平面角的余弦值.19. (本小题满分13分)已知动圆C过定点(1,0),且与直线x= —1相切.(I)求动圆圆心C的轨迹方程;(H)设A、B是轨迹C上异于原点O的两个不同点,直线OA和OB的倾斜角分别为:-和一:,①当:;亠= _时,求证直线AB恒过一定点M;2②若很亠卩为定值v(0 ::: v :::二),直线AB是否仍恒过一定点若存在,试求出定点的坐标;若不存在请说明理由•20. (本小题满分14分)1已知函数f (x) = In (x+ ) -ax,其中a R且a = 0a(I)讨论f (x)的单调区间;(n)若直线y二ax的图像恒在函数f (x)图像的上方,求a的取值范围1(川)若存在为:::0 , x2• 0 ,使得f (x1) = f (x2) = 0 ,求证:x1 x2 0.a21. 本题设有(1 )、(2)、( 3)三个选考题,每题7分,请考生任选2题作答,满分14分.如果多做, 则按所做的前两题计分•作答时,先用2B铅笔在答题卡上把所选题目对应题号右边的方框涂黑,并将所选题号填入括号中•(1) (本小题满分7分)选修4-2:矩阵与变换.3 3^一£已知矩阵A= 若矩阵A属于特征值6的一个特征向量为S = ,属于特征值1的一个特征JC d丿<1丿曰一*3 \向量a = .1-2丿(I)求矩阵A的逆矩阵;(n)计算A3的值•<4丿(2) (本小题满分7分)选修4-4:坐标系与参数方程.在平面直角坐标系xoy 中,以O 为极点,x 轴非负半轴为极轴建立极坐标系,已知曲线C 的极坐标方程为(I)写出曲线 C 的直角坐标方程和直线 I 的普通方程 (n)若 P( - 2,-4),求 |PM|+|PN| 的值.(3) (本小题满分7分)选修4-5:不等式选讲 设函数 f(x)=|x — 4|+|x - 3|,(I)求f(x)的最小值 m(n)当 a+2b+3c=m(a,b,c € R)时,求 a 2+ b 2+c 2的最小值.2019年福州市高中毕业班质量检测 数学(理科)试卷参考答案及评分标准1 —10 DABCA DCBBD16.解:(1)甲厂抽取的样本中优等品有乙厂抽取的样本中优等品有(II) 的取值为1, 2, 3. .......................... 5分v -4cosr ,直线I 的参数方程为(t 为参数),两曲线相交于M,N 两点.11.9612.1/313.014.18+ 2.3 cm 2 15.80427件,优等品率为—.10 左848件,优等品率为10 51 21 7 7 12故 的数学期望为(E ') 1 — 2 — 3 —二一 ........................... 13分15 15 15 517.解:(l) f (x) = 2cos 2 x . 3sin 2xA JIJ[ JI令-2k ?x z 2x2k 二,k Z ,26 22兀 n 兀 兀解得 2k … _2 x 岂 2k 二-即 k 二-一 一 x 一 k 二■一 ......... 4 分3 3 3 6JIJI■/[0,-]< f(x)的递增区间为[0,6】........... 6分 二二 1(n )由 f (C ) =2sin(2C —)1=2,得 sin(2C —)二—6 6 213二二 5二,’而C 0,二,所以2C,亘,所以2C 得C8分616 6 丿6P( =1)C8C2Cwi15P(C 1015 P ( =3)C83 10715= cos2x 、、3si n2x 1 =2sin2xsin A sin B1 26 3因为向量 m =(1,sinA)与向量n=(2,sinB)共线,所以a 1由正弦定理得:一=—① ................ 10分b 2由余弦定理得:c 2 = a 2 - b -2abcos —,即 a 2+b 2— ab=9 ② ........ 1 2分 3k =1即 EG=1 .............................. 8 分 T设平面DBG 的法向量为m =(X, y, Z ), •/ G(0,1,0),由①②解得a = ... 3, b = 2』313分18•解:(I )证明:•••点E 、F 分别是AB 、CD 的中点J EF//BC 又/ABC=90 °J AE 丄 EF , :•平面 AEFD 丄平面 EBCF ,J AE 丄平面 EBCF , AE 丄EF , AE 丄BE , 又 BE 丄 EF ,如图建立空间坐标系E - xyz. ........................... 2分 翻折前,连结AC 交EF 于点G ,此时点G 使得AG+GC 最小.1EG= — BC=2,又•/ EA=EB =2 .2则 A(0,0,2),B(2,0,0),C(2,4,0), D(0,2,2),E(0,0,0),G(0,2,0),J =( -2,2,2),CG=(-2,-2,BD 丄 CG ...................... 5 分(n )解法一:设 EG=k,:AD //平面EFCB ,.点D 到平面EFCB 的距离为即为点 A 到平面EFCBC1=1 一2 V=AE — (7 k )又V ADGES四形ADGE3?B E=3(2' 2V B- ADGE = V D- GBCF ,'4 23(2 k)=3(7 -k),的距离..BG =(—2,1,0), BD =(—2,2,2),…h BD =0 2x+2y + 2z = 0 则: ,即n 1 BG =0 -2x y =04取 x = 1,则 y = 2,z = — 1,A n =(1,2, -1)...................... 10 分由于所求二面角 D-BF-C 的平面角为锐角(n )解法二:由解法一得 EG=1,过点D 作DH _ EF,垂足H,过点H 作BG 延长线的垂线垂足 O ,连接 OD. T 平面 AEFD 丄平面 EBCF,. DH _平面EBCF , OD _ OB,所以三DOH 就是所求 的二面角D- BG- C 的平面角 ..... ........ 9分2由于HG=1,在也OHG 中OH =三匸5 ,DH 又 DH=2,在:DOH 中 tan . DOH 511分OH所以此二面角平面角的余弦值为 丄6. .................. 1:分619. 解:(I )设动圆圆心 M(x,y),依题意点M 的轨迹是以(1,0)为焦点,直线x=— 1为准线的抛物线 ........ 2分 其方程为y 2=4x.- ................ 3分(n )设 A(X 1,y 1),B(X 2,y 2).2 2由题意得X 1枚2(否则■-二二)且X 1X 2丰(则X 1二丫1, X 2二匹44所以直线AB 的斜率存在,设直线AB 的方程为y=kx+b , 则将 y=kx+b 与 y 2=4x 联立消去 x,得 ky 2— 4y+4 b=0面BCG 的一个"(0,0,1)则 cos<I m II r )2| 所以此二面角平面角的余弦值为13分mm >=4 4b由韦达定理得 Yi 亠y 2 =—, y 1 y 2 = ------------- ................ 6分k k① 当= _时,tan : tan 1: =1所以上上二1,也 - ym = 0 , .................................. 7分2X i x 2—b 所以y i y 2=16,又由※知:y i y 2=—-所以b=4k;因此直线AB 的方程可表示为y=kx+ 4k,所以直线AB 恒 k过定点(一4,0)............ 8分■J T② 当.::■ 为定值”0 ::: V :::二)时若二=—,由①知,2直线AB 恒过定点 M (— 4,0) ............... 9分 当';_ 时,由「• - _ J ,得 tan J - tan (芒-1:,)=24所以直线AB 恒过定点(-4,) ............ 12分tan 6所以当二-2时,直线AB 恒过定点(—4,0).,「"兀4当时直线AB 恒过定点(-4,) . ........... 13分2tan 日120. 解:(I)f(x)的定义域为(-一,;).a1其导数f (x) = —- a =1 x +a1① 当a ::: 0时,f '(x) • 0 ,函数在(-丄,;)上是增函数; 2分atan”:亠 tan : 1 - tan : tan :4( % y 2) y i y 2 -16将※式代入上式整理化简可得此时,直线AB 的方程可表示为4b- 4 ky=kx + 4 k ,所以b= 4k11分2a xax+ 11②当a 0时,在区间(-,0) 上, f'(x) 0;在区间(0,+ m)上,f'(x):::0 .a1所以f(x)在(-一,0)是增函数,在(0,+ m )是减函数. ....... 4分a1(II)当a :::0时,取x = e -a1 1 1则f (e ) = 1 -a(e ) = 2 -ae 0 ae -1 = a(e ),不合题意.a a a2」1当 a . 0时令 h(x) = ax 一 f (x),则 h(x)=2ax_ln(x ) ...................... 6 分a问题化为求h(x) 0恒成立时a 的取值范围•1 .2a(x+p 由于h(x) =2a牛 ......... 7分1 1 xx -aa1 1 i.在区间(-,-)上,h '(x) 0 ;在区间(-一,•::)上,h '(x ) 0 .a 2a 2a1 1-h(x)的最小值为h( ),所以只需h( ) 02a 2a1 1 1 1 e即 2a () -ln()0, ln1, a .................... 9 分2a2a a 2a21 (川)由于当a :: 0时函数在(-一,;)上是增函数,不满足题意,所以a 0a1 构造函数:g(x)二 f (-X )- f(x)( x :: 0) a1 1.g (x)二 ln( x)「ln(x ) 2ax ........................... 11 分a a,/、1 1小2ax小则g(x ^^-^2^v^::0贝 y x xx 2a aa、 11所以函数g(x)在区间(一一,0)上为减函数.T 一一 £捲£0,则g(xj > g(0) = 0,a a于是 f (- xj- f (x )> 0,又 f (xj = 0,f (- xj> 0= f(X 2),由 f (x)在(0,址)上为减函数可知21. (1)(本小题满分7分)选修4-2 :矩阵与变换2 3 一 ~ 3-(3 d ) • 3d - 3c = 0的两个根为6和1,c+d = 6 1 = 2 3 3" ,.A =、3c — 2d = -2 d = 42 4解:(I )法一:依题意, x 2 -x 1.即 x x 2 014分所以A 4「3■'■■■ -'d丄3 3)故 d=4,c=2.- A =............. 2 分<2 4丿(2)(本小题满分7分)选修4-4 :坐标系与参数方程.解:(I )(曲线C 的直角坐标方程为y 2=4x,直线I 的普通方程x — y — 2=0. (4)x = _2+空 t| +42y _ _4 I. 2代入y 2=4x,得到t 2 -12J2t + 48 =0,设M,N 对应的参数分别为t i ,t 2则 11 ' 12 =12 \2,11t 2 - 48所以 |PM|+|PN|= |t i +t 2|= 12.2 ............. 7 分 (3))(本小题满分7分)选修4-5 :不等式选讲解:(I )法 1: f(x)=|x — 4|+|x — 3|> |(x — 4)— (x — 3)|=1, 故函数f(x)的最小值为1. m =1.4分A 3-1法二:A 2 -14=2 X633 A分*3、 |429〕.严丿= 1434丿152r— J 4 22」A3—13伦7 129 丫-1电6 130^4巾5 21 丫3 3) 〔87 129、14 22 人2 4 丿(86 130 y7分(n )直线I 的参数方程为(t 为参数),2x - 7, x _ 4法2: f (x ) = * 1,3 兰x< 4 . ----------------- 1分1-2 x, x v 3x> 4 时,f(x) > 1;x<3 时,f(x)>1,3 < x<4 时,f(x)=1, ----------------- 3 分故函数f(x)的最小值为1. m=1. ............. 4分2 2 2 2 2 2 2(n )由柯西不等式(a +b +c )(1 +2 +3 )泊+2b+3c) =1 ------------------ 5 分1故a2+b2+c2> - ............... 6 分14113当且仅当a二一,b二-,c —时取等号........7分14 7 14。
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2014年福州市高中毕业班质量检测 数学(理科)试卷参考答案及评分标准1—10 DABCA DCBBD11.96 12.1/3 13.0 14.18+32 cm 2 15.804216. 解:(I)甲厂抽取的样本中优等品有7件,优等品率为7.10 乙厂抽取的样本中优等品有8件,优等品率为84.105=………………4分(II)ξ的取值为1,2,3. ………………5分12823101(1),15C C P C ξ⋅===………………7分21823107(2),15C C P C ξ⋅===………………9分 157)3(3100238=⋅==C C C P ξ………………11分 所以ξ的分布列为………………12分故17712123.1515155E ξξ=⨯+⨯+⨯=的数学期望为()………………13分17. 解:(I)2()2cos 2f x x x =+=cos 221x x +=2sin 216x π⎛⎫++ ⎪⎝⎭……………2分令-222,262k x k k Z πππππ+≤+≤+∈,解得322322ππππ+≤≤-k x k 即63ππππ+≤≤-k x k …………4分[0,]2x π∈,∴f (x )的递增区间为]6,0[π………………6分(Ⅱ)由21)62sin(2)(=++=πC C f ,得21)62sin(=+πC而()0,C π∈,所以132,666C πππ⎛⎫+∈ ⎪⎝⎭,所以5266C ππ+=得3C π=8⋅⋅⋅⋅⋅⋅⋅⋅⋅分 因为向量)sin ,1(A =与向量)sin ,2(B =共线,所以sin 1sin 2A B =, 由正弦定理得:21=b a ①……………10分 由余弦定理得:3cos2222πab b a c -+=,即a 2+b 2-ab =9 ②………12分由①②解得32,3==b a ……………13分18. 解:(Ⅰ)证明:∵点E 、F 分别是AB 、CD 的中点,∴EF //BC又∠ABC =90°∴AE ⊥EF ,∵平面AEFD ⊥平面EBCF , ∴AE ⊥平面EBCF ,AE ⊥EF ,AE ⊥BE , 又BE ⊥EF , 如图建立空间坐标系E ﹣xyz .……………2分 翻折前,连结AC 交EF 于点G,此时点G 使得AG+GC 最小. EG =12BC =2,又∵EA=EB =2. 则A (0,0,2),B (2,0,0),C (2,4,0), D (0,2,2),E (0,0,0),G (0,2,0), ∴=(﹣2,2,2),CG=(-2,-2,0)∴BD CG ⋅=(﹣2,2,2)(-2,-2,0)=0,∴BD ⊥CG ………………5分(Ⅱ)解法一:设EG=k ,AD ∥平面EFCB ,∴点D 到平面EFCB 的距离为即为点A 到平面EFCB 的距离.S 四形GBCF =12[(3- k )+4]×2=7-k D GBCF V S AE 四形GBCF -\=鬃13=2(7)3k -又B ADGE ADGE V S BE 四形-= 13=2(2)3k +,B ADGE D GBCF V V --=2,∴4(2)3k +=2(7)3k -,1k ∴=即EG =1…………………8分 设平面DBG 的法向量为1(,,)n x y z =,∵G (0,1,0),∴(2,1,0),BG =- BD =(-2,2,2),则 1100n BD n BG ⎧⋅=⎪⎨⋅=⎪⎩ ,即222020x y z x y -++=⎧⎨-+=⎩ 取x =1,则y =2,z =-1,∴(1,2,1)n =-…………………10分面BCG 的一个法向量为2(0,0,1)n =则cos<12,n n>=1212||||n n n n =…………………12分由于所求二面角D-BF-C 的平面角为锐角,所以此二面角平面角的余弦值为6……………………13分 (Ⅱ)解法二:由解法一得EG =1,过点D 作DH ⊥EF ,垂足H ,过点H 作BG 延长线的垂线垂足O ,连接OD. ∵平面AEFD ⊥平面EBCF,∴ DH ⊥平面EBCF ,∴OD ⊥OB,所以DOH ∠就是所求的二面角D BG C --的平面角. …………9分由于HG =1,在∆OHG 中5OH =,又DH=2,在∆DOH 中tan DHDOH OH∠==分所以此二面角平面角的余弦值为6.…………13分19. 解: (Ⅰ)设动圆圆心M (x ,y ),依题意点M 的轨迹是以(1,0)为焦点,直线x =-1为准线的抛物线………2分 其方程为y 2=4x .- …………3分(Ⅱ)设A (x 1,y 1),B (x 2,y 2).由题意得x 1≠x 2(否则αβπ+=)且x 1x 2≠0,则4,4222211y x y x == 所以直线AB 的斜率存在,设直线AB 的方程为y=kx+b , 则将y=kx+b 与y 2=4x 联立消去x ,得ky 2-4y +4b =0 由韦达定理得kby y k y y 4,42121==+-------※…………6分 ①当βα+=2π时,tan tan 1αβ⋅=所以121212121,0y y x x y y x x ⋅=-=,…………7分所以y 1y 2=16,又由※知:y 1y 2=kb4所以b =4k ;因此直线AB 的方程可表示为y=kx+4k ,所以直线AB 恒过定点(-4,0). …………8分②当αβ+为定值(0)θθπ<<时.若βα+=2π,由①知, 直线AB 恒过定点M (-4,0) …………9分当2πθ≠时,由αβθ+=,得tan tan()θαβ=+=tan tan 1tan tan αβαβ+-=16)(42121-+y y y y将※式代入上式整理化简可得:k b 44tan -=θ,所以θtan 44+=k b ,…………11分此时,直线AB 的方程可表示为y=kx +θtan 44+k ,所以直线AB 恒过定点)tan 4,4(θ-…………12分 所以当2πθ=时,直线AB 恒过定点(-4,0)., 当2πθ≠时直线AB 恒过定点)tan 4,4(θ-.…………13分20. 解:(I)f (x )的定义域为),1(+∞-a. 其导数'()a xf x a ax x a=-=-++2111………1分 ①当0a <时,'()0f x >,函数在),1(+∞-a上是增函数;…………2分 ②当0a >时,在区间(,)a-10上,'()0f x >;在区间(0,+∞)上,'()0f x <. 所以()f x 在(,)a-10是增函数,在(0,+∞)是减函数. …………4分 (II)当0a <时, 取1x e a=-,则11()1()2()011f e a e a ae e e a a a a-=--=->-=->, 不合题意.当0a >时令()()h x ax f x =-,则1()2ln()h x ax x a=-+………6分问题化为求()0h x >恒成立时a 的取值范围.由于'12()12()211a x a h x a x x a a+=-=++ ………7分 ∴在区间(,)a a --112上,0)('<x h ;在区间),21(+∞-a 上,0)('>x h . ()h x ∴的最小值为1()2h a -,所以只需1()02h a->即1112()ln()022a a a a ⋅---+>,1ln 12a ∴<-,2ea ∴>………9分(Ⅲ)由于当0a <时函数在),1(+∞-a上是增函数,不满足题意,所以0a >构造函数:()()()g x f x f x =--(10x a-<<) 11()ln()ln()2g x x x ax a a∴=--++………11分则2'22112()20111ax g x a x x x a a a=-+=<-+- 所以函数)(x g 在区间1(,0)a -上为减函数. 110x a-<<,则1()(0)0g x g >=, 于是()()f x f x -->110,又1()0f x =,()()f x f x ->=120,由()f x 在,)+∞(0上为减函数可知21x x >-.即120x x +>…………………14分21. (1)(本小题满分7分)选修4-2:矩阵与变换 解: (Ⅰ)法一:依题意,⎩⎨⎧==∴⎩⎨⎧-=-=+42,2236d c d c d c .⎪⎪⎭⎫⎝⎛=4233A . ………… 2分 所以⎪⎪⎪⎪⎭⎫ ⎝⎛--=-213121321A…………4分 法二:033)3(0332=-++-=----c d d dcλλλλ即的两个根为6和1,故d =4,c =2. ⎪⎪⎭⎫⎝⎛=∴4233A …………2分所以⎪⎪⎪⎪⎭⎫ ⎝⎛--=-213121321A-…………4分 (Ⅱ)法一:⎪⎪⎭⎫ ⎝⎛-41=2⎪⎪⎭⎫ ⎝⎛11-⎪⎪⎭⎫⎝⎛-23…………5分 A 3⎪⎪⎭⎫⎝⎛-41=2×63⎪⎪⎭⎫ ⎝⎛11-13⎪⎪⎭⎫ ⎝⎛-23=⎪⎪⎭⎫ ⎝⎛434429…………7分法二:⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛⎪⎪⎭⎫ ⎝⎛=1308612987423322142115;221421154233423332A A A 3⎪⎪⎭⎫ ⎝⎛-41=⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛-⎪⎪⎭⎫ ⎝⎛434429411308612987…………7分 (2)(本小题满分7分)选修4-4:坐标系与参数方程.解:(Ⅰ)(曲线C 的直角坐标方程为y 2=4x , 直线l 的普通方程x -y -2=0. ………..4分(Ⅱ)直线l 的参数方程为⎪⎪⎩⎪⎪⎨⎧+-=+-=t y t x 224222(t 为参数), 代入y 2=4x , 得到0482122=+-t t ,设M ,N 对应的参数分别为t 1,t 2 则048,2122121>==+t t t t所以|PM |+|PN|=|t 1+t 2|=212…………7分(3) )(本小题满分7分)选修4-5:不等式选讲解:(Ⅰ)法1: f (x )=|x -4|+|x -3|≥|(x -4)-(x -3)|=1,故函数f (x )的最小值为1. m =1. …………4分法2:⎪⎩⎪⎨⎧<-<≤≥-=3,2743,14,72)(x x x x x x f .------------------1分x ≥4时,f (x )≥1;x <3时,f (x )>1,3≤x <4时,f (x )=1,----------------3分故函数f (x )的最小值为1. m =1. …………4分(Ⅱ)由柯西不等式(a 2+b 2+c 2)(12+22+32)≥(a +2b +3c )2=1----------5分故a 2+b 2+c 2≥141-…………6分 当且仅当143,71,141===c b a 时取等号…………7分。