重庆南开中学高2016级高一下(数学)单元测试题
一、选择题(每题5分) (1)不等式x1的解集为( ▲ ) x(A),1∪1,(B)1,0∪1, (C),0∪1,(D)1,
(2)等比数列an满足a6a2a4,a125,则其公比q( ▲ ) (A)625(B)25 (C)5(D)5 (3)已知a,bR,c0,,则“abc0”是“a2bc0”的( ▲ ) (A)既不充分也不必要条件(B)充分不必要条件 (C)必要不充分条件(D)充分必要条件
(4)已知向量a3,k,b1,2,若bab12,则实数k( ▲ ) (A)1 (B)2 (C)4(D)2
(5)已知a,b0,a2b3,则3b6ab的最大值为( ▲ )
A.3 B.6 C.9 D.3 (6)若圆xy2axa50与直线x2ay60有且仅有一个公共点,则正实数a( ▲ )
222231 1960 C.3 D.
13 A.1 B.
(7)已知数列an满足a10,对任意nN,有3an1an8n10,则下列数列是等
*比数列的是( ▲ )
A.an4n1 B.an4n3 C.an4n1 D.an4n3
(8)取棱长为1正方体ABCDA(不考虑表面、边界)点P,使三棱锥PABD11BC11D1内
体积大于 A.
1的概率为( ▲ ) 611 B. 4611 C. D.
812(9)已知fx,gx是定义在R上,周期分别为T1,T2的周期函数.若要使
fxgx,fxgx也为定
义在R上的周期函数,则必须满足( ▲ ) A.T1T2Q B.
T1Q T2 C.T1T2Q D.T1T2Q
uuuruuuruuruuuruuruur(10)已知ABC满足ABACBABCCACB,则下列不等式一定成立的是( ▲ )
A.tanAtanBtanC B.tanCtanBtanA C.tanAtanBtanC 222CtanBtanA 222D.tan(第Ⅱ卷非选择题共100分)
二、填空题(本大题6个小题,每小题5分,共25分)
2(11)已知集合A1,2,B2,3,xx,xR,则A∩B ▲ 4,x1,y0的点中,横纵坐标均为整数的点的个数为 ▲ x12222(13)已知ABC内角A,B,C对边分别为a,b,c,且A,c,b,a成等差数列,则
3a ▲ c(12)满足约束条件y
(14)现有若干全等小正方体B要搭建成大正方体A:若A由8个B组成,从最上层最多
取走a1个B,使A的三视图不变;若A由27个B组成,从最上层最多取走a2个B,使A的三视图不变;···若A由(n1)个B组成,从最上层最多取走an个B,使A的三视图不变.则数列an的通项an ▲ 3
(15)若坐标平面内不存在圆与三条直线x2y2a0,axy0,
1axy3a20同时相切,则实数a ▲
三、解答题(本大题6个小题,共75分) 16.(本题满分13分)
已知函数fx3sin(Ⅰ)求fx的解析式; (Ⅱ)若fx关于直线xx2cosx2cos2x210: 22对称,将所有可能的值由小到大令为a1,a2,,an并组成3数列an,若该数列前n项和Sn13,求正整数n的最小值. 17.(本题满分13分)
已知ABC内角A,B,C对边分别是a,b,c,且
sinBsinC11sinAsinB7,:
sinAsinC8sinAsinC8(Ⅰ)求a:b:c;
(Ⅱ)若c6,求将ABC以边b为轴旋转一周所扫过空间的体积.
(18)(本题满分13分)
xx1已知函数fxloga4a21a0,1:
(Ⅰ)若a1,求fx的单调区间;
2(Ⅱ)若a1,ftmtm1ft4对任意t2,3恒成立,求实数m的
取值范围.
(19)(本题满分12分)
如图,三棱锥PABC中,ABCP4,AB,CP夹角为120,分别取
PAP,BC,PB中点E,F,G,已知AE23,AG3,cosAEF(Ⅰ)求EF的长;
(Ⅱ)求二面角AEFG的大小.
E7: 12GCFA
B
(20)(本题满分12分)
如图,圆xy4交x负半轴于A,Pa,b是直线xy6 22y上一动点,直线AP交圆于异于A的点B若b0,过P引圆的切线 切点为C,当B,C关于x轴对称时,设直线PC斜率为k: PBAa2的值.
(Ⅰ)若b0,试求kba2uuruur(Ⅱ)若a1,,求|PA||PB|的取值范围;
21.(本题满分12分)
xCO 已知数列an满足anania2nii1,3,且a11,a20,a21: (Ⅰ)若a722,求a2;
(Ⅱ)证明:对于一切sxx2k1,kN,都有anansa2ns成立.
参
一、选择题,填空题及解析
15BBBDA,610ACACC
11.2 12. 5 13. 解析:
1.考察数形结合
9. 用三角函数知识可猜出答案
10.C可能是钝角故先排除B选项.由ABACcosABABCcosBCACBcosC得
17 14. nn1 15. 2或
2ABAC得
sinAsinBsinC1BABCCACB由三角形面积公式SabsinC tanAtanBtanC21111tanA得C选项. 由于只可能C钝角,由所以排最tanAtanBtanCtanA2后成立
15.只可能三直线平行或交于一点 二、解答题及评分标准 16.(Ⅰ)fx3xx1x2sincos2cos21 2222231·····································(5分) sinxcosxsinx·
226(Ⅱ)令x62kx22kkx·························(833分)
由关于直线x2对称得 32k223231k1kkN 333232*又nNkn1∴an31n∴ 22Sn321nn13·············(10分) 442*∴3nn520nN解得n4∴n的最小值为5················(13分)
17.(Ⅰ)由正弦定理得
bc11ab7,设bc11k,ac8k,ab7kk0 ac8ac8∴a2k,b5k,c6k∴a:b:c2:5:6·······························(5分) (Ⅱ)作BDAC于D,先求BD,CD的长
222方法一:设CDx,则BD4x∴5x4x36x27 10351·····················································(8分) 10036254575757方法二:用余弦定理cosA∴AD6
606060107351,BD2∴CD···········································(8分) 10100∴BD2∴VV(大圆锥)V(小圆锥)1351577117······(13分) 31001010202x218.(Ⅰ)a1fxloga22a2x14a40∴定义域为R········(2
分)
令2u,u2au1w,u20恒递增,w在u0,a,即
x2x
x,log2a上递减
在ua,即xlog2a,上递增,又loagw递增∴增区间为
(4分) xlo2ga,·
减区间为x,log2a····················································(6分)
a10,(Ⅱ)对称轴在y轴左侧∴w恒递增又logaw递增∴fx为增函数·(·8
分)
t2t3∴tmtm1t4tt3mt1m在t2,3恒成立
t122令t1b1,2b1∴tb1∴
2b13m即
bb31m···········(10分) b33b23当bb3时等号成立验证得31,2
bb∴实数m的取值范围是,231··········································(13分) 19.(Ⅰ)∵EG,GF是PAB,PCB中位线,ABCP4,AB,CP120
∴EGGF2,EGF120∴EF23·······························(4分)
(Ⅱ)作GOEF于O,连AO,则GO1,EO3又AE23,cosAEF7 127123AO2AO22∵AG31222∴1212232
222∴AOGOAG∴GOAO······································(8分)
又GOEF,EF,AO平面AEF
∴GO平面AEF又GO平面EGF∴平面EFG平面AEF.················(12分)
20.(Ⅰ)借用二问中切线,由几何知识得PCPAPB
222222∵POaa62a12a36PCPOOC
22∴PAPBPCPOOC2a12a32a1
2222
故PAPB14,···················································(5分)
(Ⅱ)设直线PC交x轴于D,则直线AB斜率kAB由对称得BODCOD2PAD
6atanPAD a2122aa22kAB2tanPAD∴tanCODtanBOD············(921tan2PAD1kAB16a32分) ∴kOC122aa2又∵k3216aOCkPC1∴kPC16a32
122aa2∴kb16a2a2a2······························(12分) 6a8 ·
a226aa2a22321.(Ⅰ)由已知条件,a722a2a5a2故a22··················(2分) a3a2(Ⅱ)由条件anan1a2n1,anan3a2n3得
22an1a2n1a2 an3a2n3a4又由a3a2,a5a2a1a4a4a5a2
故
an1a2n1a21 an3a2n3a4a2∴数列a2n1为首项为a2,公比为a2的等比数列·······················(4分) 令
an1a1*中的n2k1kN,则2k an3a2k1a2∴数列a2n为首项为a3,公比为a2的等比数列····················(6分)
又∵a2a3∴a2na2n1
由2ns必为奇数,a2na2n1得,
a2nsa2ns1as12n2a2ns12··············(8
分)
①如果n是奇数,则anan1a故anansa2ns12n122ansans2 2·································(10分) anans·
②如果n是偶数,则ana,ansans1a故anansa2
ns12n22ns12 2·················································(12分) a2ns·
综上,对于一切正奇数s,都有anansa2ns成立