数学试题(理)
本试卷共 2 页,共 22 题。满分150分,考试用时120分钟。
一、选择题:(本大题共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。请将正确的答案填涂在答题卡上。) 1.已知集合M3,2 A.0,2,3
a,Na,b,若MN2,则MN
B.1,2,3
C.0,1,2
D.0,1,3
ii2i3i20152.已知复数z,则复数z在复平面内对应的点位于
1iA.第一象限 B.第二象限 C.第三象限 D.第四象限 3.能够把圆O:x2y216的周长和面积同时分为相等的两部分的函数称为圆O的“和 谐函数”,下列函数不是圆O的“和谐函数”的是 ..A.f(x)eeC.f(x)tanxx B.f(x)lnx3 D.f(x)4xx 44.设等差数列{an}的前n项和为Sn,若2a66a7,则S9的值为
5x5x
A.27 B.36 C.45 D.54 5.
cos2xcosxsinxdx=
A.2(21) B.21 C.21 D.22 406.下列说法正确的是 A.“若a1,则a21”的否命题是“若a1,则a21”
B.{an}为等比数列,则“a1a2a3”是“a4a5”的既不充分也不必要条件
4x0成立 D.“若tan3,则”是真命题
3 C.x0(-,0),使37.2012年初,甲、乙两外商在湖北各自兴办了一家大型独资企业.2015年初在经济指标对
比时发现,这两家企业在2012年和2014年缴纳的地税均相同,其间每年缴纳的地税按 各自的规律增长;企业甲年增长数相同,而企业乙年增长率相同.则2015年企业缴纳地 税的情况是 A.甲多 B.乙多 C.甲乙一样多 D.不能确定
x08.老师带甲乙丙丁四名学生去参加自主招生考试,考试结束后老师向四名学生了解考试情况,
四名学生回答如下: 甲说:“我们四人都没考好”; 乙说:“我们四人中有人考的好”; 丙说:“乙和丁至少有一人没考好”; 丁说:“我没考好”. 结果,四名学生中有两人说对了,则四名学生中 两人说对了. A.甲 丙 B.乙 丁 C.丙 丁 D.乙 丙
9.已知ABC的外接圆半径为1,圆心为O,且3OA4OB5OC0,则ABC的面积为
1
87 B. C. D.
555510.已知函数ysinx2cosx(0)的图象关于直线x1对称,
A.
则sin2
B.A.4 53 5 C.
3 5 D.
11.已知函数g(x)13mxxm(m0)是[1,)上的增函数.当实数m取最大值时,3x45
若
存在点Q,使得过点Q的直线与曲线yg(x)围成两个封闭图形,且这两个封闭图形
的面积
总相等,则点Q的坐标为
3) A.(0,3) C.(0,2)B.(0,2) D.(0,
x1,x0,2g(x)x4x14,若关于x的方程12.已知R,函数f(x)lgx,x0,f(g(x))
有6个解,则的取值范围为
212212 A.(0,) B.(,) C.(,) D.(0,)
323525二、填空题(本大题共4小题,每小题5分,共20分)
13.x1是函数f(x)exmln(2x)的极值点,则m的值为 .
14.已知非零向量a,b满足abab,则a与ab的夹角a,ab .
15.在ABC中,A30,2ABAC3BC,则ABC的最大角的余弦值为 . 16.定义max{a,b}表示实数a,b中的较大的数.已知数列{an}满足a1a(a0),a21, an222maxan{1an,2}(nN),若a20154a,记数列{an}的前n项和为Sn,则S2015
的值为
.
三、解答题:(本大题共6小题,共70分,解答应写出文字说明,证明过程或演算步骤) 17.(本小题满分12分)
22 如图ABC中,已知点D在BC边上,且ADAC0,sinBAC,
3AB32,BD3. (Ⅰ)求AD的长; (Ⅱ)求cosC.
18.(本小题满分12分)
已知数列{an}是等差数列,{bn}是等比数列,且a1b12,b454,
a1a2a3b2b3.
(Ⅰ)求数列{an}和{bn}的通项公式;
(Ⅱ)数列{cn}满足cnanbn,求数列{cn}的前n项和Sn.
2
19.(本小题满分12分)
如图,有一矩形钢板ABCD缺损了一角,边缘线OM上每一点到点D的距离都等于它到边AB的距离.工人师傅要将缺损的一角切割下来使剩余部分成一个五边形,若AB1m,AD0.5m,为了方便,如图建立直角坐标系,问如何画切割线EF可使剩余部分五边形ABCEF的面积最大?
20.(本小题满分12分)
各项为正数的数列an的前n项和为Sn,且满足:Sn(Ⅰ)求an;
1211anannN. 424n为奇数an,n(Ⅱ)设函数fnn,Cnf(24),nN ,求数列Cn的
f2,n为偶数 前n项和Tn.
21.(本小题满分12分)
已知函数f(x)xee1,其中tR,e2.71828L是自然对数的底数. (Ⅰ)若方程f(x)1无实数根,求实数t的取值范围;
(Ⅱ)若函数f(x)是(0,)内的减函数,求实数t的取值范围.
3
txx请考生在第22、23、24三题中任选一题作答,如果多做,则按所做的第一题记分.
22.(本小题满分10分)选修4-1:几何证明选讲
如图,AB是O的直径,CB与O相切于B,E为线段CB上一点,连接AC、 AE分别交O于D、G两点,连接DG交CB于点F. (Ⅰ)求证:C,E,G,D四点共圆;
(Ⅱ)若F为EB的三等分点且靠近E,EG1,GA3,求线段CE的长. 23.(本小题满分10分)选修4-4:坐标系与参数方程选讲
xt3lxOy 已知在直角坐标系中,直线的参数方程为,(t为参数),以坐标原点
y3t为
极点,x轴的正半轴为极轴建立极坐标系,曲线C的极坐标方程为24cos30. (Ⅰ)求直线l的普通方程和曲线C的直角坐标方程;
(Ⅱ)设点P是曲线C上的一个动点,求它到直线l的距离d的取值范围. 24.(本小题满分10分)选修4-5:不等式选讲 已知函数f(x)x1.
(Ⅰ)解不等式f(x1)f(x3)6;
(Ⅱ)若a1,b1,且a0,求证:f(ab)af().
ba理科数学参及评分标准
一、选择题:(本大题共12小题,每小题5分,共60分。) 1 2 3 4 5 6 7 8 题号 B B A D C D B D 答案 二、填空题(本大题共4小题,每小题5分,共20分) 13. 1 14.
9 C 10 A 11 C 12 D 6 15.1 16. 7254 2三、解答题:(本大题共6小题,共70分,解答应写出文字说明,证明过程或演算步骤) 17.解:(Ⅰ)因为ADAC,所以sinBACsin所以cosBADBADcosBAD, 222. ··························································································· 2分 3222cosBAD 在ABD中,由余弦定理可知,BDABAD2ABAD
4
即AD28AD150, ···························································································· 4分 解之得AD5或AD3, 由于ABAD,所以AD3. ································ 6分 (Ⅱ)在ABD中,由正弦定理可知,
BDAB,
sinBADsinADB122 又由cosBAD可知sinBAD ··························································· 8分
33ABsinBAD6 所以sinADB ··································································· 10分 BD36 因为ADBDACCC,即cosC ····································· 12分
235427, 2318.解:(Ⅰ)设an的公差为d,bn的公比为q,由b4b1q3,得q从而q3,因此bn23n1··············································································· 3分 , ·
又a1a2a33a2b2b361824,
n1a28, da2a16,故an6n4,bn23 ·········································· 6分
(Ⅱ)cnanbn4(3n2)3012123n1
n2n1令Tn134373…(3n5)3(3n2)3n1
···························· 9分 (3n2)3n ·
则3Tn134373…(3n5)3两式相减得2Tn13333…3312n17(6n7)3n (3n2)322n73n(6n7)Tn44············································· 12分 ,故Sn4Tn7(6n7)3 ·
n
19.解:由题知,边缘线OM是以点D为焦点,直线AB为准线的抛物线的一部分.
111y轴建立直角坐标系,则D(0,),M(,).
42412 边缘线OM所在抛物线的方程为yx(0x).……………………………2分
2 要使如图的五边形ABCEF面积最大,则必有EF所在直线与
2抛物线相切,设切点为P(t,t).
2则直线EF的方程为y2t(xt)t,
2即y2txt,
以O点为原点,AD所在直线为
由此可求得E,F点的坐标分别为
14t21E(,),F(0,t2). ……………………………………………………4分
8t4114t212(t) 所以SDEFS(t)28t4116t48t211,t[0,] ··································································· 7分
2t148t48t21(12t21)(4t21)所以S(t) 22tt
5
显然函数S(t)在(0,331]上是减函数,在(,]上是增函数.……………………9分 6623················ 10分 时,SDEF取得最小值,五边形ABCEF的面积最大. ·
6311此时点E,F的坐标分别为E(,),F(0,).
3412此时沿直线EF划线可使五边形ABCEF的面积最大. ············································ 12分
所以当t20.解:(Ⅰ)由Sn1211111anan①得, 当n≥2时,Sn1an12an1②; 424 424
由①-②化简得:(anan1)(anan12)0, ··············································· 2分 又∵数列{an}各项为正数,∴当n2时,anan12, 故数列{an}成等差数列,公差为2,又a1S11211a1a1, 424 解得a11,an2n1; ··························································································· 5分
an,n为奇数(Ⅱ)由分段函数f(n)n 可以得到:
f(),n为偶数2············· 7分 c1f(6)f(3)a35,c2f(8)f(4)f(2)f(1)a11; ·
当n3,nN时,
················· 9分 cnf(2n4)f(2n12)f(2n21)2(2n21)12n11, · 故当n3时,Tn51(21)(21)(223n11)
4(12n2)(n2)2nn 612n15,n15,n2不扣分 Tnn„„„„12分 最后结果写成Tn6,2nn,n32n,n2x(1t)txx0,f(x)1无负实根. 21.解:(Ⅰ)由f(x)1得xee,即xelnxlnx1lnx1t.令g(x)故有,g(x), ······································ 2分 xxx2 由g(x)0得0xe,由g(x)0得xe,
g(x)在(0,e)上单调递增,g(x)在(e,+)上单调递减.
g(x)·········································· 4分 maxg(e),g(x)的值域为(,]. · 要使得方程f(x)1无实数根,则1t1e1e11,即t1. ····························· 5分 ee (Ⅱ)f(x)etx+txetxex=etx[1txe(1t)x],由题设,
t1t 知对x0,f(x)0恒成立.不妨取x1,有f(1)e(1te)0,
而当t1时,f(1)0,故t1. ····································································· 7分
6
xx1xtx(1t)x]e2(1e2). ① 当t,且x0时,f(x)=e[1txe22xx2 而当x0时,有e1x,故1e0.所以f(x)0,
2x1时满足题意. ························ 9分 211t1t1,即ln0. ② 当t1时,01t,且
221t1t1tt(1t)x(1t)e(1t)x. 令h(x)1txe(1t)x,则h(0)0.h(x)t(1t)e1t1tln 当0x时,h(x)0,此时,h(x)h(0)0, 1t1t1t1tlnln)单增, 则当0x时,f(x)0,故f(x)在(0,1t1t1t1t 所以f(x)在(0,)内单调递减, 故当t与题设矛盾,不符合题意,舍去.
1时,函数f(x)是(0,)内的减函数. ·········································· 12分 222.解:(Ⅰ)连接BD,则AGDABD,
所以,当t 又因为ABDDAB90,CCAB90,所以CABD
所以CAGD,所以CDGE180,所以C,E,G,D四点共圆 ··········· 5分
2(Ⅱ)因为EGEAEB,则EB2,又F为EB三等分,所以EF24,FB, 33 由于C,E,G,D四点共圆,由割线定理得FGFDFEFC,
2 FB与⊙O相切于B,由切割线定理得FGFDFB
8,故CE2 ···················································· 10分 323.解:(Ⅰ)直线l的普通方程为:3xy330; ······································ 2分 曲线C的直角坐标方程为:(x2)2y21 ················································ 5分 (Ⅱ)设点P(2cos,sin)(R),则
2 所以FEFCFB,则FC|2cos()53||3(2cos)sin33|6 d2253531,1] ·所以d的取值范围是[································································· 10分 2224.解:(Ⅰ)由题意,原不等式等价为x2x26,
x22x,令g(x)x2x24,2x2 ······················································· 3分
2x,x2 不等式的解集是(,3][3,) ····································································· 5分
ba22 只需证(ab1)(ba)
(Ⅱ)要证f(ab)af(),只需证|ab1||ba|,
7
而(ab1)2(ba)2a2b2a2b21(a21)(b21)0, 从而原不等式成立. ·························································································· 10分
8