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福州三中2024-2025学年第一学期高三第七次质量检测
数 学 答 案
题号 1 2 3 4 5 6 7 8
答案 C C A C C A A C
题号 9 10 11 12 13 14
答案 AD ABD AC −120
答案第1页,共7页
2 7 x 2 + y 2 = 2
1.【详解】 i 5 = i ,故 a + b i = i ,所以 a = 0 , b = 1 , a + b = 1 .故选:C.
2.【详解】 A = x x 2 − x 0 = x x ( x − 1 ) 0 = { x x 1 或 x 0 } ,
B = x ln ( x + 1 ) 0 = x ln ( x + 1 ) ln 1 = x x 0 ,所以AB=(1,+).故选:C.
3.【详解】圆 C : ( x − 2 ) 2 + y 2 = 1 中圆心为 C ( 2 , 0 ) ,半径 r = 1 ,
圆心到直线 x − y = 0 的距离: d =
2
2
= 2 ,则 P Q
m in
= 2 − 1 .故选:A.
4.【详解】因为 a , b 为单位向量,
由 3a−5b =7,所以
(
3 a − 5 b
) 2
= 4 9 9 a
2
− 3 0 a b + 2 5 b
2
= 4 9 ,即 9 − 3 0 a b + 2 5 = 4 9 a b = −
1
2
,
设a与a−b夹角为,则 c o s
a
a
(
a
a
b
b
)
a
a
2
(
a
a
b
b
) 2
1
1
2
1
2
1
2
1
2
3
=
−
−
=
−
−
=
−
−
−
−
+
= ,
π
又0,π,所以= .故选:C.
6
5.【详解】抛掷一枚质地均匀的骰子朝上的点数,
设A表示事件“点数是1点” B , 表示事件“点数是3点或5点”,
C 表示事件“点数是偶数点” D , 表示事件“点数是奇数点”,
P ( A ) =
1
6
1
P(B)=
3
P ( C ) =
1
2
1
P(D)=
2
P ( A B ) =
1
2
, , , , ,
P ( A B ) = P ( A ) + P ( B ) 此时满足 ,但P(A)P(B),故选项A错误;
P ( A D ) = P ( B D ) =
1
2
,但P(A)P(B) ,故选项B错误;
P ( A C ) = P ( B C ) = 0 成立,但P(A)P(B),故选项D错误;
对于选项C A , B P ( A ) 0 , P ( B ) 0 ,对于随机事件 ,且 ,则
由 A = A B + A B 得P(A)=P(AB)+P(AB),又B=BA+BA,得 P ( B ) = P ( B A ) + P ( B A ) ,
又因为 P ( A ) = P ( B ) ,所以P(AB)+P(AB)=P(BA)+P(BA),则P(AB)= P(AB),故必要性成立,
反之,由P(AB)= P(AB)可得P(AB)+P(AB)=P(BA)+P(BA),所以P(A)=P(B),故充分性成立,所
以C选项正确.故选:C .
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}6.【详解】根据题意可知,每次挖去的三角形面积是被挖三角形面积的
答案第2页,共7页
1
3
,
所以每一次操作之后所得图形的面积是上一次三角形面积的
2
3
,
由此可得,第 n 次操作之后所得图形的面积是 S
n
= 1
2
3
n
,
即经过4次操作之后所得图形的面积是 S
4
= 1
2
3
4
=
1
8
6
1
.故选:A.
7. S C 【详解】如图, 是球 O 的直径,则 S B C S A C
2
= = ,
所以SA=1=SB= AB,AC = 3=BC,
在△SAC中,过A作 A M ⊥ S C 于 M ,连接 B M ,易证 B M ⊥ S C ,所以 S C ⊥ 平 面 A B M ,
3
又因为在△ABM 中,AM = BM = ,AB=1,所以
2
S
△ A B M
=
4
2
,则 V =
1
3
S
△ A B M
S C =
6
2
.
故选:A.
8.
a
b
+
b
a
= 3 c o s C a 2 + b 2 = 3 a b c o s C = 3 a b
a 2 +
2
b
a
2
b
− c 2
【详解】由 及余弦定理得: ,
a 2 + b 2 = 3 c 2 s in 2 A + s in 2 B = 3 s in 2 C 则 ,由正弦定理得: ,
1 1 ( )
所以 (1−cos2A)+ (1−cos2B)=31−cos2C ,即3cos2C−cos(A−B)cos(A+B)−2=0,
2 2
3
cos(A−B)=−
6
3 c o s 2 C
6
3
c o s C 2 0 又 ,所以 ,
3
cosC =
2
c o s C = −
4
9
3
3 c o s C =
a
b
+
b
a
2 c o s C =
2
3
解得: 或 ,由于 ,所以 .故选:C.
9.【详解】因为 y = 2 s in x c o s x = s in 2 x ,向右平移
π
6
个单位得 f ( x ) = s in 2
x −
π
6
= s in
2 x −
π
3
,
则最小正周期为 T =
2 π
2
= π ,故A选项正确;
π π π π 5π
令− +2kπ2x− +2kπ,解得− +kπx +kπ,
2 3 2 12 12
π 5π
所以单调递增区间为 − +kπ, +kπ ,kZ,故B选项错误;
12 12
π π 5π kπ
令2x− = +kπ,解得x= + ,kZ,故C选项错误;
3 2 12 2
π π
令2x− =kπ,解得x= +kπ,kZ所以函数
3 6
f ( x )
π
的对称中心为 +kπ,0,kZ,故D选项正确.
6
故选:AD.
10.【详解】设双曲线的半焦距为c,则 c = a 2 + 1
c 2
, = ,
a 5−1
a2+1 5+1 5−1 5+1
由题意知 = a2 = ,c2 = ,
a 2 2 2
a 2 e = a c = 1 ,A正确.
A
2
( a , 0 ) , B ( 0 ,1 ) , F ( − c , 0 ) , A
2
B = ( − a ,1 ) , F B = ( c ,1 ) , A
2
B F B = 1 2 − a c = 0 ,B正确.
x2
对于C,双曲线 −y2 =1的渐近线方程为xay=0,
a2
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}所以顶点到渐近线距离
答案第3页,共7页
d =
a
a
2 + 1 2
=
a
c
=
1
e
,C错误.
对于D,因为 A
2
B F B = 0 ,所以 A
2
F ⊥ F B ,所以 AFB为直角三角形,且
2
A
2
B F 9 0 , A
2
F a c = = + ,
所以 AFB的外接圆半径为
2
a +
2
c ,故 A
2
F B 外接球面积 S = π a +
2
c 2 = π
4
( a 2 + c 2 + 2 a c ) = 2 +
4
5 π ,D
正确.故选:ABD.
11.【详解】 f ( 2 x + 1 ) 为奇函数, f ( − 2 x + 1 ) = − f ( 2 x + 1 ) ,
令x=0,则 f (1)=0;用x替换 2 x ,则 f ( − x + 1 ) = − f ( x + 1 ) ,
又 f ( x + 2 ) 为偶函数, f ( − x + 2 ) = f ( x + 2 ) ,
令 x = 1 ,则 f ( 3 ) = f ( 1 ) = 0 ;用 x + 1 替换 x ,则 f ( − x + 1 ) = f ( 3 + x ) ,
f ( x + 3 ) = − f ( x + 1 ) ,用x−1替换 x ,则 f ( x + 2 ) = − f ( x ) ,
f ( x + 4 ) = − f ( x + 2 ) = f ( x ) ,则 f ( x ) 的一个周期为4,
f(1)=a+b=0
由 ,解得
f(0)+ f(3)=1+b=−1
a
b
=
=
2
− 2
,故A正确;
f ( 2 0 2 3 ) = f ( 5 0 5 4 + 3 ) = f ( 3 ) = 0 ,故B错误;
由 f (−x+2)= f (x+2),得 f ( − x ) = f ( x + 4 ) = f ( x ) ,得 f ( x ) 为偶函数,故C正确;
x 0 ,1 时, f (x)=2x−2, f(0)+ f(1)=−10, f x 不关于
1
2
, 0
对称,故D错误.故选:AC.
12.【详解】 (1 − 2 x ) 5 展开式第 r + 1 项 T
r + 1
= C r5 ( − 2 x ) r = C r5 x r ( − 2 ) r ,
r = 2 时, x C 25 x 2 ( − 2 ) 2 = 4 0 x 3 , r = 3 时, 2 C 35 x 3 ( − 2 ) 3 = − 1 6 0 x 3 , 4 0 x 3 − 1 6 0 x 3 = − 1 2 0 .
a
3
= − 1 2 0 .故答案为: − 1 2 0 .
1 1
13.【详解】由题意得:=80,=5,+2=90,故P(X 90)=P(X +2)= − 0.9545=0.02275,
2 2
所以 1 2 0 0 0 .0 2 2 7 5 2 7 .故答案为:27.
14.【详解】由 f ( x ) = e x − e 2 − x 得 f(x)=ex +e2−x 0,所以 f(x)=ex −e2−x在定义域 R 上单调递增,
又因为 f ( 2 − x ) = e 2 − x − e x = − f ( x ) ,所以 f ( x ) = e x − e 2 − x 关于(1,0)对称,
则 f(a)=−f(2−a),即 f(a)+ f(2−a)=0,
因为 f(a)+ f(b)=0,所以b=2−a,即a+b−2=0,
所有满足 f(a)+ f(b)=0的点(a,b)中,有且只有一个在圆 C 上,则直线x+y−2=0与圆 C 相切,
−2
假设圆心C(0,0),所以r =d = = 2,所以圆C可以是x2+y2 =2,
1+1
故答案为: x 2 + y 2 = 2 .(注:圆心到直线 x + y − 2 = 0 的距离为半径即可).
a
15.解:(1)已知S = n +n2+1,nN*,
n 2
a
当n=1时,a = 1 +2,a =4; ·············································································· 1分
1 2 1
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}当n=2时,
答案第4页,共7页
a
1
+ a
2
=
a
2
2 + 5 , a
2
= 2 ,所以 a
1
+ a
2
= 6 . ·················································· 2分
因为 S
n
=
a
2
n + n 2 + 1 ①,所以 S
n + 1
=
a
n2 + 1 + ( n + 1 ) 2 + 1 ②. ················································· 3分
②-①得, a
n + 1
=
a
n2 + 1 −
a
2
n + ( n + 1 ) 2 − n 2 ,整理得 a
n
+ a
n + 1
= 4 n + 2 , n N * , ······················· 6分
所以(a n+1 +a n+2 )−(a n +a n+1 )= 4(n+1)+2 −(4n+2)=4(常数),nN*, ························· 7分
所以a +a 是首项为6,公差为4的等差数列. ····················································· 8分
n n+1
(2)由(1)知, a
n
+ a
n + 1
= 4 n + 2 , n N * .
所以S =(a +a )+(a +a )+(a +a )+ +(a +a )
20 1 2 3 4 5 6 19 20
=(41+2)+(43+2)+(45+2) +(419+2)
···················································· 10分
=4(1+3+5+ +19)+210
10(1+19)
=4 +210=420 ·············································································· 13分
2
16.解:(1)连接DB交AC于点O,连接PO.
因为ABCD是菱形,所以BD⊥AC,且O为BD的中点, ············································ 2分
因为PB=PD,所以PO⊥BD. ············································································ 3分
又因为AC,PO平面APC,且AC PO=O,所以BD⊥平面APC. ··························· 4分
又 B D 平面ABCD,所以平面APC⊥平面ABCD; ··················································· 5分
(2)取AB中点M,连接DM交AC于点H,连接PH.
因为 B A D
3
= ,所以△ABD是等边三角形,所以DM⊥AB.
又因为PD⊥AB, P D D M = D ,PD,DM 平面PDM,
所以AB⊥平面PDM.所以AB⊥PH. ····································································· 6分
由(1)知BD⊥PH,且 A B B D = B ,所以PH⊥平面ABCD. ··································· 7分
由ABCD是边长为2的菱形,在△ABC中, A H =
c
A
o s
M
3 0
=
2
3
3
,AO=ABcos30= 3.
2 3 4 3 8
由AP⊥PC,在△APC中,PH2 = AHHC = = ,所以
3 3 3
P H =
2
3
6
. ················· 8分
以O为坐标原点,OB、OC分别为x轴、y轴建立如图所示空间直角坐标系, ················ 9分
( ) ( ) 3 3 2 6
则A 0,− 3,0 ,B(1,0,0) ,C 0, 3,0 ,H0,− ,0,P0,− , ,
3 3 3
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}( )
所以AB= 1, 3,0 ,
答案第5页,共7页
C B =
(
1 , − 3 , 0
)
, B P =
− 1 , −
3
3
,
2
3
6
, ········································ 10分
设平面PAB的法向量为 n
1
= ( x
1
, y
1
, z
1
) ,
3 2 6
n BP=0 −x − y + z =0
所以 1 1 3 1 3 1 ,令
n AB=0
1 x 1 + 3y 1 =0
y
1
= 1 得 n
1
=
− 3 ,1 , −
2
2
. ······················· 11分
设平面PBC的法向量为 n
2
= ( x
2
, y
2
, z
2
) ,2
所以
n
n
2
2
B
C
P
B
=
=
0
0
− x 2 −
x
3
3
2
−
y 2 +
3 y
2
2
3
=
6
0
z 2 = 0 ,令 y
2
= 1 得 n
2
= ( 3 ,1 , 2 ) . ························· 12分
设平面PAB与平面PBC的夹角为.
n n
所以cos= cosn,n = 1 2
1 2 n n 1 2
=
( − 3 ) 2 +
−
1 2
3
+
−
3
2
+
2
1
2
1
−
(
2
2
−
3 ) 2
2
+ 1 2 + ( 2 ) 2
=
3
3
, ········ 14分
所以平面PAB与平面PBC夹角的余弦值为
3
3
. ······················································· 15分
17.解:(1)记事件A:直径约 1 0 m m 的结节在1年内发展为恶性肿瘤,
事件B:该项无创血液检测的检查结果为阴性, ························································ 1分
由题意, P ( A ) = 0 .2 % , P ( A ) = 9 9 .8 % , P ( B | A ) = 1 5 % , P ( B | A ) = 8 5 % , P ( B | A ) = 8 5 % , P ( B | A ) = 1 5 % ,
······················································································································· 3分
因为B= BA+BA,
所以
= 1 5 %
P (
B
0
) =
.2 %
P (
+
B
8
A
5
+
%
B
A
9
)
9
=
.8
P
%
( B
=
A
0
)
.8
+
4
P
8 6
( B A ) = P ( B | A ) P ( A ) + P ( B | A ) P ( A )
, ······································································· 5分
所以患者甲检查结果为阴性的概率为0.8486. ··························································· 6分
(2) P ( A B ) = P ( B | A ) P ( A ) = 1 5 % 0 .2 % , ································································· 7分
P ( A | B ) =
P
P
( A
( B
B
)
)
=
1 5 % 0
1 5
.2
%
%
+
0
8
.2
5 %
%
9 9 .8 %
0 .0 0 0 3 5 . ··············································· 9分
所以患者甲的检查结果为阴性,他的这个结节在1年内发展为恶性肿瘤的概率为0.00035. 10分
(3)记参加该项检查的1000位患者中,获得20万元赔付的有X人,
X B (1 0 0 0 , 0 .0 0 0 3 5 ) ,则EX =10000.00035=0.35, ··················································· 12分
记保险公司每年在这个项目上的收益为Y元,
Y =2001000−2105X, ······················································································ 13分
则EY =2001000−2105EX =1.3105, ··································································· 14分
所以保险公司每年在这个项目上的收益估计为13万元. ············································· 15分
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}18.解:(1)设动点M 坐标为(x,y),则根据题意得
答案第6页,共7页
( x − 2 ) 2 + y 2 = 2 x −
1
2
, ··············· 2分
两边同时平方,化简可得 x 2 −
y
3
2
= 1 ,所以曲线 E 的方程为 x 2 −
y
3
2
= 1 ; ······················· 4分
(2)由题设点 P ( x
0
, y
0
) ,
因为点 P 不在 x 轴上,即 y
0
0 ,所以曲线 E 在点 P 的切线斜率存在,设为 k , ·············· 5分
则在点 P 的切线方程为: y − y
0
= k ( x − x
0
) , ····························································· 6分
联立方程组:
y
x
−
2 −
y
0
y
3
=
2
k
=
(
1
x − x
0
)
,
整理得: ( 3 − k 2 ) x 2 − 2 k ( y
0
− k x
0
) x − ( y
0
− k x
0
) 2 − 3 = 0 ,··········································· 7分
因为双曲线的渐近线为 y = 3 x ,所以 k 2 3 , = 4 k 2 ( y
0
− k x
0
) 2 + 4 ( 3 − k 2 ) ( y
0
− k x
0
) 2 + 3 ,
令Δ=0,得 k 2 ( x 20 − 1 ) − 2 k x
0
y
0
+ y 20 + 3 = 0 . ·························································· 8分
因为点 P ( x
0
, y
0
) 在双曲线上,所以 x 20 − 1 =
y
3
20
,即 y 20 + 3 = 3 x 20 ,所以 k 2 y 20 − 6 k x
0
y
0
+ 9 x 20 = 0 ,
因为 y
0
0 所以两边同时除以 y 20 ,解得 k =
3 x
0
y
0
.
所以在点P的切线方程为 y − y
0
=
3 x
0
y
0
( x − x
0
) ,即 x
0
x −
y
03
y
= 1 . ································ 10分
因为P(x ,y ) ,
0 0
P Q ⊥ l ,所以 Q
1
2
, y
0
,
所以直线PQ中垂线 C D 方程为
x =
x
0
+
2
1
2 ,即 x =
2 x
04
+ 1
, ······································· 11分
1 2y 5 y
因为A(2,0) ,Q ,y ,所以直线AQ的斜率为k =− 0 ,线段AQ的中点为E , 0 ,
2 0 AQ 3 4 2
3
所以直线AQ中垂线EF 的斜率为k = , ·························································· 13分
EF 2y
0
所以直线 A Q 中垂线 E F 的方程为 y −
y
2
0 =
2
3
y
0
x −
5
4
.
联立直线 C D 与直线 E F
x
y
=
−
2
y
2
x
0
04
=
+ 1
2
3
y
0
x −
5
4
,得外心坐标
2 x
04
+ 1
,
3 x
0
−
4
6
y
+
0
2 y 20
. ··· 15分
2x +1
将外心横坐标x= 0 代入过点
4
P 的切线方程 x
0
x −
y
03
y
= 1 ,
3x −6+2y2
化简得到 y = 0 0 ,与外心的纵坐标相等.
4y
0
所以曲线E在P点的切线经过△PQA的外心. ························································· 17分
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}19.解:(1)解:当a=−1时,
答案第7页,共7页
f ( x ) = e x s in x − x ,
则 f '( x ) = e x ( s i n x + c o s x ) − 1 = 2 e x s in x + π
4
− 1 . ··················································· 1分
π
当x 0, 时,
2
x +
π
4
π
4
,
3 π
4
,所以
2
2
s in
x +
π
4
1
π
,所以1 2sinx+ 2. ······· 3分
4
π 又ex 1,所以 2sinx+ 1,所以
4
f (' x ) 0 恒成立, ············································ 4分
所以 f(x)在区间
0 ,
π
2
上单调递增,
所以 f(x)的最小值为 f ( 0 ) = 0 . ··············································································· 6分
(2)解:由已知可得 f ( 0 ) = 0 ,则 f ( x ) 在区间
0 ,
π
2
上有且只有1个零点.
f '( x ) = e x s i n x + e x c o s x + a ,
令g(x)=exsinx+excosx+a, x
0 ,
π
2
.
则g(x)=ex(sinx+cosx)+ex(cosx−sinx)=2excosx, ··················································· 7分
因为g(x)=2excosx0在区间
0 ,
π
2
上恒成立,
所以 f '(x)在区间
0 ,
π
2
上单调递增.
所以,当x=0时, f '( x ) 有最小值 f (' 0 ) = a + 1 ;当 x = π
2
时, f '( x ) 有最大值 f ' π
2
= e π2 + a , 9分
当a−1时,有 f (' 0 ) = a + 1 0 ,则 f '( x ) 0 恒成立,
则 f(x)在区间 0 , π
2
上单调递增,所以 f ( x ) f ( 0 ) .
又 f ( 0 ) = 0 ,所以 f ( x ) 在区间
0 ,
π
2
上无零点,不符合题意,舍去; ······························· 11分
当 a−e 2 时,有 f ' π 2 =e π 2 +a0恒成立,则 f(x)在区间 0, π 2 上单调递减,所以 f (x) f (0).
又 f ( 0 ) = 0 ,所以 f ( x ) 在区间
0 ,
π
2
上无零点,不符合题意,舍去; ······························· 13分
当 时,有
−e2 a−1
f (' 0 ) = a + 1 0 , f
' π
2
= e
π2
+ a 0 .
π
又 f '(x)在区间 0, 上单调递增,
2
根据零点的存在定理可得, x
0
0 ,
π
2
,使得 f '(x)=0.
当 x [ 0 , x
0
) 时, f '( x ) 0 , f ( x )
π
单调递减:当x
x
0
,
2
时, f '(x)0, f ( x ) 单调递增.
又 f(0)=0, f
π
2
= e
π2
+
π
2
a ,要使 f(x)在区间
0 ,
π
2
上有且只有一个零点,
π π 2 π
则e2 + a0,解得a− e2. ·············································································· 16分
2 π
2 π
又 ,所以− e2 a−1.······································································· 17分
−e2 a−1
π
{#{QQABLYiAogAoAAAAARgCAw1QCEMQkhGAAQgGQFAEsAIACBFABCA=}#}