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2022年哈三中第二次高考模拟考试数学试卷(理工类)答案一、选择题BDCDBCAABCBC二、填空题13:314:215:20216:8三、解答题17.(Ⅰ))34sin(3)(xxf4分增区间)(3108,328Zkkk2分对称轴)(3
104Zkkx2分(Ⅱ)32,334x2分值域3,232分18.(Ⅰ)样本平均数为.......................................2众数为12..........................
.......4(Ⅱ)..........................................................................6而81860.,.........
.................................................................9∴818605.,B~X,∴的数学期望0934818605..XE..............
........................................................1219.(Ⅰ)法1面EADF⊥面BEFC且DFEFDF⊥面BEFCCE面BEFCCEDF
2又CEBF且BF∩DFFCE⊥面DBF
4法2面EADF⊥面BEFC且AEEF,BEEF,AEBE如图所示,建立以E为坐标原点,EA
,EF,EB所在直线为x轴,y轴,z轴的空间直角坐标系1
则E(0,0,0)C(0,2,2)B(0,0,2)D(2,2,0)F(0,2,0)EC=(0,2,2)BD=(2,2,-2)BF=(0,2,-2)设面DBF的法向量为m,00mBDmBF,
则m(0,1,1)3EC∥m,即直线CE面DBF4(Ⅱ)过B作BHAE交AE于点H由已知可得
AEEF,BEEF,AE∩BEEEF⊥面ABE,且AEB为折成二面角的平面角,即3AEBBH面ABEEFBH,取BF的中点I如图所示,建立以H为坐标原点,HA,HI,HB所在直线为x轴,
y轴,z轴建立的空间直角坐标系5则3B(0,0,)E(-1,0,0)3C(0,2,)D
(1,2,0)设Mm(1,,0)3EB=(1,0,)3EC=(1,2,)2EMmm=(2,,0)(0)设面EMC的法向量为1n,1100nECnEM,则
143mnm(,-2,)7设直线BE与面EMC所成角为,则1112sincos2||||EBnEBnEBn,解得1m
9则面EMC的法向量为113n(,-2,),面DEM的法向量为20n(,0,1)则1212126cos4||||nnnnnn
,11设面与面EMC所成角为,为锐角,则126coscos4nn,1220.(Ⅰ)31a时
,1ln2xxxf,22eef,切线方程:eexey223222........................................................3分(Ⅱ)当0a,xf在,,110;当310a
xf在,,11,330aa;当31a,xf在,,,aa33110;当31a时,xf在,0.............................7分(III)令03ln2axxxf,ax,x3121
。①当3ea时,xf在,e,22221aeefxf,32eae。②当3ea时,22min213ln363213ln3aaaaaaafxf,182331ea
,综上,1823312e,ea........................12分21.(Ⅰ)221,1,2222abebb又,22a,12:22yxC................
.............................................................................................2分(Ⅱ)(ⅰ)设00,
yxP,过P点与椭圆C相切的直线方程为00yxxky222200yxyxxky得0224212000022ykxxkxykxk,0得01222000220ykyxkx,121kk,AB为圆O的直径,即32AB...
......................................................6分(ⅱ)设2211,,,yxNyxM,设PM:11yxxky,222211yxyxxky0得112111122yxxy
xk,PM:2211yyxx,同理PN:2222yyxx,MN的方程22222200yxyyxx得04443200220yxxxy,02002134yxxx,202021344yyxx,
22040202031222yyyyMN。O到MN的距离202042yxd,2020312yySOMN,令2221120,,t,ty,223222,ttSOMN........12分22.(Ⅰ)2211
:29Cxy..........................................................................2222:14xCy.............................
.............................................................4(Ⅱ)设(2cos,sin)Q,圆心1(0,2)C213sin4sin8CQ.....................
.....................................................61max2213CQ.....................................................
.....................................7max221133PQ...........................................................
...............................9当2sin3时取“=”................................................................................
.........1023.(Ⅰ)由题意得,,当时,不等式化为,解得,;当时,不等式化为,无解;当时,不等式化为,解得,则不等式的解集为或..........................................................4(Ⅱ),即.∵..............
..................6当且仅当时等号成立,∴2212nm...............................8∴8222223221212nmnm,即xfnm1
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