解:记“甲理论考核合格”为事件A1;“乙理论考核合格”为事件A2;“丙理论考核合格”为事件A3;
记Ai为Ai的对立事件,i?1,2,3;记“甲实验考核合格”为事件B1;“乙实验考核合格”为事件B2;“丙实验考核合格”为事件B3;
(Ⅰ)记“理论考核中至少有两人合格”为事件C,记C为C的对立事件 解法1:P?C??P?A1A2A3?A1A2A3?A1A2A3?A1A2A3? ?P?AAA?3?128 ?0.9?0.? ?0.90 2?P0.?3AAA?123??P1A2A?A3??P1?A 2A3A0?.7 ?00?.9?0.2?0.7?0.?10.?8解法2:P?C??1?PC?1?PA1A2A3?A1A2A3?A1A2A3?A1A2A3
?1??PA1A2??????A??P?AAA??P?AAA??P?AAA??
?3123123123?1??0.1?0.2?0.3?0.9?0.2?0.3?0.1?0.8?0.3?0.1?0.2?0.7?
?1?0.098?0.902
所以,理论考核中至少有两人合格的概率为0.902
(Ⅱ)记“三人该课程考核都合格” 为事件D
P?D??P???A1?B1???A2?B2???A3?B3???
?P?A1?B1??P?A2?B2??P?A3?B3?
?P?A1??P?B1??P?A2??P?B2??P?A3??P?B3?
?0.9?0.8?0.8?0.8?0.7?0.9
?0.254016 ?0.254
所以,这三人该课程考核都合格的概率为0.254
19.本小题主要考察长方体的概念、直线和平面、平面和平面的关系等基础知识,以及空间想象能力和推理能力。满分12分
解法一:(Ⅰ)证明:取CD的中点K,连结MK,NK ∵M,N,K分别为AK,CD1,CD的中点
∴MK//面ADD1A1,NK//面ADD1A1∵MK//AD,NK//DD1
(Ⅱ)设F为AD的中点
∵P为A1D1的中点 ∴PF//D1D ∴PF?面ABCD
作FH?AE,交AE于H,连结PH,则由三垂线定理得AE?PH
从而?PHF为二面角P?AE?D的平面角。 在Rt?AEF中,AF?a2,EF?2a,AE?172a
∴面MNK//面ADD1A1 ∴MN//面ADD1A1
a,从而FH?AF?EF?2AE?2a172?a2a17
在Rt?PFH中,tan?PFH?PFFH?DD1FH?172172 故:二面角P?AE?D的大小为arctan 第 17 页
(Ⅲ)S?NEP?112444作DQ?CD1,交CD1于Q,由A1D1?面CDD1C1得A1C1?DQ
S矩形ECDP?1BC?CD1?1?a?a?4a?2252a
∴DQ?面BCD1A1 ∴在Rt?CDD1中,DQ?∴VP?DEN?VD?ENP?13CD?DD1CD1?12a?a5a52?225a 16S?NEP?DQ?34a?5a?a
3方法二:以D为原点,DA,DC,DD1所在直线分别为x轴,y轴,z轴,建立直角坐标系,则 A?a,0,0?,B?a,2a,0?,C?0,2a,0?,A1?a,0,a?,D1?0,0,a?
∵E,P,M,N分别是BC,A1D1,AE,CD1的中点 ∴E????a?,2a,0?,P?,0,a?,M?2??2???????3a(Ⅰ)MN???a,0,2?4a?3a?,a,0?,N??4?a?0,a,?2???, ??? 取n??0,1,0?,显然n?面ADD1A1
???????????? MN?n?0,∴MN?n
又MN?面ADD1A1 ∴MN//面ADD1A1
?? ?(Ⅱ)过P作PH?AE,交AE于H,取AD的中点F,则F?a??a? 设H?x,y,0?,则HP???x,?y,a,HF??x,?y,0?????2??2??????????a?,0,0?∵ ?2??????a又AE???,2a,0??
2???a2a??????????x?2ay?0 由AP?AE?0,及H在直线AE上,可得: ?2?4??4x?y?4a解得x?3334a,y?217a
?????????????????????8a2a2a???????8a∴HP???,?,a?,HF???,?,0? ∴HF?AE?0 即HF?AE
17171717????????????∴HP与HF所夹的角等于二面角P?AE?D的大小
????????????????HP?HF2cosHP,HF?????????? 21HP?HF22121??????????????(Ⅲ)设n1??x1,y1,z1?为平面DEN的法向量,则n1?DE,n1?DN ?????aa?????? 又DE??,2a,0?,DN??0,a,2?2????????a?,DP?,0,a???
2???故:二面角P?AE?D的大小为arccos
第 18 页
?ax1?2ay1?0????x1??4y1?2 ∴? 即 ? ∴可取n1??4,?1,2?
?z1??2y1?2y?az?011??2??????DP?n12a?2a4a ∴P点到平面DEN的距离为d? ????16?1?421n1????????????????????????21DE?DN8 ∵cosDE,DN??????????, sinDE,DN?
8585DE?DN ∴S?DEN? ∴VP?DEN?????????1????????DE?DN?sinDE,DN?213S?DEN?d?13?218a?2218?a
324a21a6
20.本小题主要考察等差数列、等比数列的基础知识,以及对数运算、导数运算和极限运算的能力,同时考查分类讨论的思想方法,满分12分。
解:(Ⅰ)由题意,?an?是首项为1,公差为2的等差数列 前n项和Sn?1?1?2?n?1?22?n?n,lnSn?lnn?2lnn
2Un?2?ln1?ln2???lnn??2ln?n!?
(Ⅱ)Fn?x??eUn22n?n!??x2n??n!?22n?n!?2?x2n?x2n2n Fn?x??x'2n?1
nn'2k?1kTn?x???F?x???xk?1k?1?x?1?x2n???0?x?1?21?x? ???n?x?1??2n?x?1?x??x?1?2?1?x?limTn?x?Tn?1?x?n?????2n1?x?lim?1?n??1?x2n?2?n???lim?1n??n?1???1??2n??1?x??lim??n???1?2?x??2n??x???0?x?x?1??1?
?x?1?
21.本小题主要考察双曲线的定义和性质、直线与双曲线的关系、点到直线的距离等知识及解析几何的基本思想、方法和综合解决问题的能力。满分12分。
解:由双曲线的定义可知,曲线E是以F1??2,0?,F2?2,0?为焦点的双曲线的左支,
第 19 页
且c?2,a?1,易知b?1
22 故曲线E的方程为x?y?1?x?0? 设A?x1,y1?,B?x2,y2?,由题意建立方程组? 消去y,得?1?k2?x2?2kx?2?0 又已知直线与双曲线左支交于两点A,B,有
2?1?k?0?22????2k??8?1?k??0?? 解得??2k?x1?x2??02?1?k??2?x1x2??02?1?k??y?kx?1?x?y?122
2?k??1
又∵ AB??1?k?x1?x2?221?k?2?x1?x2?2?4x1x2
22?2??2k?2?21?k???4??221?k1?k???1?k??2?k? ?1?k?22依题意得 2?1?k??2?k??1?k?2222?63 整理后得 28k?55k?25?0
42∴k?257或k?254 但?2?k??1 ∴k??552
故直线AB的方程为x?y?1?0
2????????????设C?xc,yc?,由已知OA?OB?mOC,得?x1,y1???x2,y2???mxc,myc? ∴?mxc,myc?????x1?x2m,y1?y2??,?m?0? m?2k22又x1?x2?2kk?1m2??45,y1?y2?k?x1?x2??2?k?1?2?2k?12?8
??∴点C??45,8?
???m?将点C的坐标代入曲线E的方程,得
80m2?64m2?1
得m??4,但当m??4时,所得的点在双曲线的右支上,不合题意
∴m?4,C点的坐标为?5,2
C到AB的距离为52??5?2?1?5?2???1?2?2?????13
∴?ABC的面积S?
12?63?13?3 第 20 页

