This is the answer in Chinese.
First, multiple choice questions
( 1)c
(2)b
(3)b
⑷a⑸b⑹d
(7)b
(8)d
(9)c
( 10)a
( 1 1)a
( 12)d
Second, fill in the blanks
( 13)-6 ( 14) ( 15) ( 16)
Third, answer questions.
(18) solution:
(1) Because
,
Derived from cosine theorem
So bd
2
+ad
2
=
abdominal muscle
2
, so bd
advertisement
Police again
Bottom abcd, bd
pitch diameter of thread
So bd
flat gasket
therefore
dad
Bottom fuze (abbreviation of base detonating)
(2) As shown in the figure, D is the coordinate origin, the length of ad is the unit length, and the ray da is
The positive semi-axis of the shaft establishes the spatial rectangular coordinate system d-
, then
,
,
,
Let the normal vector of the plane pab be n=(x, y, z), then
that is
Therefore, we hope that n=
Let the normal vector of the plane pbc be m, then
M=(0,- 1,
)
Therefore, the cosine of dihedral angle a-pb-c is
(19) solution
(1) According to the test results, the product quality yield of Formula A is
Therefore, the estimated ratio of high-quality products produced by Formula A is 0.3.
According to the test results, the frequency of producing high-quality products by Formula B is as follows
Therefore, the estimated ratio of high-quality products produced by Formula B is 0.42.
(2) The quality index value of 100 product produced by Formula B is within this range.
The frequencies are 0.04, 0.054 and 0.42, respectively, so
p(x=-2)=0.04,p(x=2)=0.54,
p(x=4)=0.42,
In other words, the distribution list of x is
The mathematical expectation of x ex=-2×0.04+2×0.54+4×0.42=2.68.
(20)
solve
(i) Let m(x, y) be given by known b (x, -3) and a (0,-1).
therefore
=(-x,- 1-y),
=(0,-3-y),
=(x,-2)。
From the meaning of the question (
+
)?
=0,
That is, (-x, -4-2y)? (x,-2)=0。
So the equation of curve c is y=
x
-2.
(i) Establishment
, by
Yes, when?
When,
. but
, so
while
When,
, available
When x
( 1,+
), h (x) < 0, available.
h(x)>0
So when x>0 and x
In 1, f(x)- (
+
)>0, that is, f(x) >
+
.
(ii) Set 0 < k< 1. Because when x
( 1,
)、(k- 1)(x
2
+ 1)+2x & gt; 0, so
(x)>0 and
H( 1)=0, so when x
( 1,
),h(x)>; 0, available
h(x)& lt; 0, which contradicts the topic.
(3) Let k
1. At this moment
(x)>0, and h( 1)=0, so when x.
( 1,+
),h(x)>; 0, available
h(x)& lt; 0, which contradicts the topic.
On the whole, the value range of k is (-
,0]
(22)
Solution:
(I) connect de, in delta ade and delta △acb according to the meaning of the question,
ad×ab=mn=ae×ac,
that is
And ∠dae=∠cab, so △ade∽△acb.
Therefore ∠ade=∠acb.
So c, b, d and e are four * * * cycles.
(ⅱ)m=4,
When n=6, equation x
2
-14x+mn=0, two of them are X ..
1
=2,x
2
= 12.
therefore
ad=2,ab= 12。
Take the midpoint G of ce and the midpoint F of DB, cross G and F respectively as the vertical lines of ac and ab, and the two vertical lines intersect at point H to connect dh. Because C, B, D and E are * * * circles, the center of the circle where C, B, D and E are located is H and the radius is dh.
Because ∠ a = 90.
, so GH∨ab,
HF∑AC。
hf=ag=5,df=
( 12-2)=5.
Therefore, the radius of the circle where C, B, D and E are located is 5.
Questioner's question
20 1 1-06- 13
1 1:07
Well, thank you. What about the two volumes? Report to the authorities
My supplement
20 1 1-06- 13
18:46
First, multiple choice questions
bbadc
cbaad
this
Second, fill in the blanks
( 13)0 ( 14)-4/3
( 15)6
(16) Root number 2/3
Third, short answer questions
( 17)c= 15
( 18)0.8 20
(20)an= 1- 1/n
History multiple-choice questions: Jiangsu volume
cddba
abccd
Agricultural Bank of China
dbada