Math and science papers
First,? Multiple choice questions? BBDC？ DBBCACAA
Second,? Fill in the blanks? 13、 1? 14、? 15、? 16、
Third, answer questions.
17.？ (1) According to the meaning of the question, because in a triangular prism, the edge is a rectangle, and the midpoint of it intersects with the point and the edge, then in the bottom Z, you can know it by using similar triangles, and then you can know it; ........................... scored six points.
(2) If, then using the midpoint of, Pythagorean theorem shows that the volume of triangular prism is
18.？ Solution: (1) f ′ (x) =-3x2+m,
∵f(x)=﹣x3+mx is increasing function at (0, 1), ∴f'(x)=﹣3x2+m≥0 is constant at (0, 1),
That is, m≥3x2, m≥3,-2 points.
So the set A is [3, +∞); So m=3, ∴ f' (x) = 3x2+3,
∵, an > 0, ∴=3an, i.e. =3,
∴ sequence {an} is the geometric series of the first term, and the common ratio of 3, so an = 3n? -Six points.
(2) From (1), bn = nan = n &；; #8226; 3n，
∴sn= 1&； #8226; 3+2 & amp； #8226; 32+3 & amp； #8226; 33+…+n & amp； #8226; 3n①
3Sn= 1。 #8226; 32+2 & amp； #8226; 33+3 & amp； #8226; 34+…+n & amp； #8226; 3n+ 1②
① ② Germany, ② SN = 3+32+33+…+3N+N&; #8226; 3n+ 1=﹣n&； #8226; 3n+ 1
Simplification, sn = >. -12 points.
10 point
It is 6.5438+million yuan. -654.38+02 points.
20.？ Solution (I) is equal with a tolerance of 2.
、.？ Say it again,
,,?
Isomorphism? , solutions or. Say it again, ................. Six points.
(2) In China. ,,.
The circumference of?
, ... 10 point
Here we go again.
Be punctual and get the most. .........................................................................................................................................................................
2 1.？ Solution: (ⅰ) F&; # 162; (x)=x(2-ax？ )，x>0。
If a≤0, f &；; # 162; (x) > 0, and f(x) increases on (0, +∞);
If a > 0, when x∈(0, a (? 2? ))，f &； # 162; (x) > 0, and f(x) increases monotonically;
When x∈(a (? 2? )、+∞)、f &； # 162; (x) < 0, and f(x) monotonically decreases ... 5 points.
(ii) According to (i), if a≤0, f(x) increases at (0, +∞),
F (1) = 0, so f(x)≤0 is not a constant.
If a > 2, when x∈(a (? 2? ), 1), f(x) decreases, and f (x) > f (1) = 0, which is irrelevant.
If 0 < a < 2, when x∈( 1, a (? 2? )), f(x) increases, and f (x) > f (1) = 0, which is irrelevant.
If a = 2, f(x) increases at (0, 1) and decreases at (1, +∞).
F (x) ≤ f (1) = 0, which meets the topic.
Therefore, a = 2, lnx ≤ x- 1 (take "=" if and only if x =1) ...
When 0 < x 1 < x2, f (x2)-f (x1) = 2lnx1(x2)-2 (x2-x1)+2.
< 2(x 1(x2)- 1)-2(x2-x 1)+2
= 2(x 1( 1)- 1)(x2-x 1)，
So x2-x1(x1) < 2 (x1(1)-1) ...12 points.
22.？ (1) It is proved that MD and circle O intersect at point T, so they are determined by the cutting line.
Reason, reason, reason
Let the radius OB=, because BD=OB and BC=OC=,
Then,,
So-five points.
(2) from (1),
So, so;
According to the angle theorem of a circle,-10 points.
23. Solution:? (1) problem.
Therefore, we only need to solve the inequality ...................................................................... 2.
At that time, the original infinitive was equivalent to, that is.
At that time, the original infinitive was equivalent to, that is.
At that time, the original infinitive was equivalent to, that is.
To sum up, the solution set of the original inequality is. ? Five points.
(2) exploit the topic.
When > 0,
. ? ........................ 10.