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Huairou Ermo 20 12 Mathematical Answers
1.C 2。 D 3。 C 4 explosive B 5。 C 6。 A seven. C 8。 A

II. Fill in the blanks (the score for this question is *** 16, with 4 points for each small question)

9.k≥ 10。 27

1 1.2 points.

(2) 2 points

12. (2 points in each space) 2,2

Iii. Answer the question (30 points for this question, 5 points for each small question)

13. solution: the original formula = =4 (the first step is to give a number 1 minute, and the second step is to give a correct result 1 minute).

14. solution: original formula = (2 points for the first step and 3 points for the correct result for the second step)

=

15. Prove that quadrilateral is isosceles trapezoid,

.2 points

Yes, the midpoint,

.3 points

.4 points

Ae = de 5 points

16. Solution: Original formula =

3 points

4 points

5 points

17. Solution: If Type A robot carries kilograms of chemical raw materials per hour, then Type B robot carries (-20) kilograms per hour, 1 minute.

According to the meaning of the question: 3 points

The score for solving this equation is .4.

It is proved to be the solution of the equation, which accords with the practical significance, so -20=80. Five points.

A: Robots A and B respectively carry 100 kg and 80 kg of chemical raw materials every hour.

18. Solution: (1) 25 (1)

(2) 50 ( 1)

Draw a bar chart (1)

(3)5 people; (The score of this column for the equation is 1, and the answer given is 1).

Iv. Answer (this question ***2 1 point, 19, 6 points for 20 questions, 5 points for 2 1 question and 4 points for 22 questions)

19.

(1) Method 1: Connect as shown in the figure.

1 point

Say it again,

, 2 points

Namely.

Is the tangent of 0.3 point.

(2) Solution: Starting from (1), it is an isosceles right triangle. Four points.

, is the diameter,

.5 points

.

.6 points

20. Solution: (1)∵ Quadrilateral ABCD is a square.

∴∠BCF+∠FCD=900

BC=CD 1。

∵△ECF is an isosceles right triangle,

∴∠ECD+∠FCD=900.CF=CE 2。

∴∠BCF=∠ECD.

∴△BCF≌△DCE 3 points

(2) In △BFC, BC=5, CF=3, ∠ BFC = 900. ∴ BF = .4 points.

∵△bcf≌△dce,∴de=bf=4,∠bfc=∠dec=∠fce=900.∴DE∥FC

∴△DGE∽△CGF 5 points

∴ DG: GC = DE: CF = 4: 3.6。

2 1. Solution: (1) Point A( 1, 1) is on the image of the inverse proportional function.

K=2。 The analytical formula of the inverse proportional function is:. 1.

The analytical formula of linear function is:

Point A( 1, 1) is on the image of the linear function. Two points.

The analytical formula of linear function is

(2) Point A( 1, 1)

① when ∠OB 1A=90 o, that is, B 1A⊥OB 1.

∠AOB 1 = 45o∴b 1a = ob 1。 ∴ B 1 (1, 0) 4 o'clock.

② When ∠ o a b2 = 90 ∠ ao b2 = ∠ ab2o = 45,

B 1 is the midpoint of B2OB2 (2,0).

To sum up, the coordinates of point B are (1, 0) or (2,0) .5 minutes.

22.( 1)5 1.

(2) 15

V. Answer questions (this question is ***2 1 point, 23 questions are 6 points, 24 questions are 7 points, and 25 questions are 8 points)

23. Solution: (1)∫ The image of quadratic function passes through point C(0, -3),

∴ c =-3。 1.

Substituting points A (3 3,0) and B (2 2,3) gives the following results.

Solution: a= 1, b=-2.

-2 points.

The formula is:, so the symmetry axis is x= 1.

(2) According to the meaning of the question, BP = OQ = 0.1t.

Point b and point c have the same ordinate,

∴BC∥OA.

After passing through point B, point P is BD⊥OA, PE⊥OA, and the vertical feet are D and E respectively.

To make a quadrilateral ABPQ isosceles trapezoid, only PQ = AB, Pb ≠ AQ is needed.

That is QE = AD = 1.

QE = OE-OQ =(2-0. 1t)-0. 1t = 2-0.2t

∴2-0.2t= 1.

T = 5。 -Three points.

It is also known that Pb = 0.5 and AQ = 2.5.

That is, when t=5 seconds, the quadrilateral ABPQ is an isosceles trapezoid.

② Let the intersections of the symmetry axis with BC and X axis be f and g respectively.

The symmetry axis x= 1 is the perpendicular bisector of the line segment BC,

∴ BF = CF = OG = 1。 -Four points.

∫BP = OQ,

∴PF=QG.

And ≈PMF =∠QMG,

∴△MFP≌△MGQ.

∴MF=MG.

Point m is the midpoint of FG-5.

∴S=

=

By =

∴S=

BC=2,OA=3。

It takes 20 seconds to move from point P to point C and stop moving.

∴0<; t≤20

When t=20 seconds, the area s has a minimum of 3-6 points.

24. Solution: (1)

Set and intersect at this point, and then

∫ The midpoint is 1 point.

There are two more points.

∴ swept area = 3 points

(2)①, 4 points.

(2) When, take the midpoint, then

5 points

6 points

Yes,

At this moment,

To sum up, 7 o'clock

25.

(1) proves that ∵ is an equilateral triangle.

1 point

Is the midpoint

2 points

The trapezoid is an isosceles trapezoid. 3 points

(2) solution: in equilateral,

Four points.

∵ ∴

Five points.

(3) Solution: ① If yes, yes.

Then quadrangles and quadrangles are parallelograms.

6 points

When, yes.

Then quadrangles and quadrangles are parallelograms.

When or, a quadrilateral with two vertices at p, m and a, b, c and d is a parallelogram.

At this time, the parallelogram has four .7 points.

② It is a right triangle.

When the minimum value is taken,

∴ is the midpoint of the year, and

Eight points.

(Note: The solutions to many problems in this volume are not unique. Please give points according to the grading standard. )