一、选择题:1~8小题,每小题4分,共32分,下列每小题给出的四个选项中,只有一项符合题目要求的,请将所选项前的字母填在答题纸指定位置上. ...(1)【答案】:C
x2?x??,所以x?1为垂直的 【解析】:lim2x?1x?1x2?x?1,所以y?1为水平的,没有斜渐近线 故两条选C lim2x??x?1(2)【答案】:C
(3)f'(x)?ex(e2x?2)?(enx?n)?(ex?1)(2e2x?2)?(enx?n)??(ex?1)(e2x?2)?(nenx?n)
所以f(0)?(?1)(3)【答案】:(B) 【解析】:由x?'n?1n!
x2?y2解得y的下界为2x?x2,由x2?y2?2解得y的上界为
(D). 将极坐标系下的二重积分化为X?型区域的二重积分得4?x2.故排除答案(C)
到被积函数为f(x?y),故选(B).
(4)【答案】:(D) 【解析】:考察的知识点是绝对收敛和条件收敛的定义及常见的p级数的收敛性结论.
22?(?1)i?1?n?3(?1)n1 nsin?绝对收敛可知??;?2??条件收敛可知??2,故答案为(D)
2ni?1n(5)【答案】:(C)
0【解析】:由于??1,?3,?4??01?1c3?11?c1c41?1?11?0,可知?1,?3,?4线性相关。故
c1选(C)
(6)【答案】:(B)
?100??100??????1?1【解析】:Q?P?110?,则Q???110?P,
?001??001?????故
?100??100??100??1??100??1?????????????Q?1AQ???110?P?1AP?110????110??1110?1??????001??001??001??????2??001??2?????????
故选(B)。 (7)【答案】:(D)
【解析】:由题意得, f?x,y??fX?x?fY?y????1,0?x?1,0?y?1,
其它.?0,P?X2?Y2?1?=??f?x,y?dxdy,其中D表示单位圆在第一象限的部分,被积函数是1,
D故根据二重积分的几何意义,知PX?Y?1=?22??4,故选(D).
(8)【答案】:(B)
【解析】:从形式上,该统计量只能服从t分布。故选B。
具体证明如下:
X?X2X1?X2,由正态分布的性质可知,1与?2X3?X4?22??X3?X4?2???2???X1?X22?X3?X4?2均服从标准正态分布且相互独立,可知?t?1?。
22??X3?X4?2???2???二、填空题:9?14小题,每小题4分,共24分,请将答案写在答题纸指定位置上. ...(9)【答案】:e-2X1?X22? 1cosx?sinx【解析】:lim?tanx?x???e1??lim??tanx?1???cosx?sinx??x?4
41??4 lim=lim??tanx?1???cosx?sinx?x?cosx?sinxx???44tanx?tan???????tan?x???1?tanx?tan?4??4??=lim
????x?4-2sin?x??4????????x?1?tanx?tan????4??4??=lim
????x?4-2?x??4??=2 -2=-2
所以lim?tanx?x?1cosx?sinx??e1??lim??tanx?1???cosx?sinx??x?4=e-2 4(10)【答案】:4 【解析】:
dydxx?0?f'?f(x)?f'(x)x?0?f'?f(0)?f'(0)?f'??1?f'(0)
dydx?4
x?0由f(x)的表达式可知f'?0??f'(?1)?2,可知(11)【答案】:2dx?dy
【解析】:由题意可知分子应为分母的高阶无穷小,即
f(x,y)?2x?y?2?o(x2?(y?1)2),
所以
?z?x(0,1)?2,
?z?y(0,1)??1,故dz(0,1)?2dx?dy
(12) 【答案】:4ln2 【解析】:被积函数为1的二重积分来求,所以
S??dy?ydx??dy?dx?0422y44yy433?4ln2??4ln2 22(13)【答案】:-27
【解析】:由于B?E12A,故BA*?E12A?A*?|A|E12?3E12, 所以,|BA*|?|3E12|?33|E12|?27*(?1)??27. (14)【答案】:
3 4【解析】:由条件概率的定义,PABC?其中PC?1?P?C??1???P?ABC?P?C?,
12?, 331P?ABC??P?AB??P?ABC???P?ABC?,由于A,C互不相容,即AC??,
2??P?AC??0,又
ABC?AC,得P?ABC??0,代入得P?ABC??证明过程或演算步骤.
13,故PABC?. 24??三、解答题:15—23小题,共94分.请将解答写在答题纸指定位置上.解答应写出文字说明、...
22ex?e2?2cosxex2?2cosx(15)【解析】:lim?limelimx?0x?0x?0x4?2?2cosx?1x4
x2?2?2cosx?limx?0x4?x2x4?2x?2?2?1???o?x2??24!??(泰勒公式)?limx?0x4
4x+o?x2?=lim124x?0x1=12(16)(本题满分10分)
解析】:由题意知,区域D??(x,y)|0?x?1,x?y???1??,x?y 如图所示所以
??exydxdy?lim?dx?Dx?00x11xxexxydy
1xxO 1 x 1?1??lim?exx?y2?x?00?2?dx1?1x??lim?exx???dxx?00?2x2?111?lim?exdx??exx2dx02x?00111?lime?1?exx2?2?exxdx
002x?011?lim?1?2?xdex02x?0111?lim?1?2exx??exdx002x?011?lim??1?2?e?(e?1)???2x?02??????????(17)【解析】:1)设成本函数为C(x,y),由题意有:Cx?(x,y)?20?x, 2x2?D(y), 对x积分得,C(x,y)?20x?4再对y求导有,Cy?(x,y)?D?(y)?6?y, 再对y积分有,D(y)?6y?12y?c 2x21?6y?y2?c 所以,C(x,y)?20x?42x21?6y?y2?10000 又C(0,0)?10000,故c?10000,所以C(x,y)?20x?422)若x?y?50,则y?50?x(0?x?50),代入到成本函数中,有
x21C(x)?20x??6(50?x)?(50?x)2?1000042 3?x2?36x?115504所以,令C?(x)?3x?36?0,得x?24,y?26,这时总成本最小C(24,26)?11118 23)总产量为50件且总成本最小时甲产品的边际成本为Cx?(24,26)?32,表示在要求总产量为50件时,在甲产品为24件,这时要改变一个单位的产量,成本会发生32万元的改变。
1?xx2?cosx?1?,可得 (18)【解析】:令f?x??xln1?x2f'?x??ln?ln1?x1?x2?x??sinx?x1?x1?x?1?x?2
1?x2x??sinx?x1?x1?x21?x1?x2?ln??x?sinx21?x1?x1?x1?x21?x2?0,?1,所以?x?sinx?0, 当0?x?1时,有ln1?x1?x21?x21?xx2?cosx?1??0 故f?x??0,而f?0??0,即得xln1?x2'1?xx2?cosx??1。 所以xln1?x2