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Duanjia road
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Section b
Figure 8 Classmate: Have you ever been to Huangshan Mountain? On the uphill road of Huangshan Mountain, there are some intermittent steps, as shown in Figure 8, which is a schematic diagram of steps A and B.. The numbers in Figure 8 indicate the height (unit: cm) of each step, and the variance p, b, d, g, f, a, h, (65438+) of d, e, c and d. Please use the relevant statistical knowledge you have learned (mean, median, variance and extreme range) to answer the following questions: (1) What are the similarities and differences between these two steps? (2) Which step is more comfortable? Why? (3) In order to facilitate tourists' walking, it is necessary to reform the uphill path. For these two steps, please put forward reasonable reconstruction suggestions under the condition that the number of steps remains unchanged. 26. (The full score of this small question is 8) In the plane rectangular coordinate system, the coordinate of the center o is (-3,4), and a circle is made in the coordinate plane with the radius r.. (1) When r is, (2) When r is, the circle O has two intersections with the coordinate axis; (3) When r, the circle O has three intersections with the coordinate axis; (4) When r, the circle O has four intersections with the coordinate axis; 27. (The full score of this small question is 10) In order to increase the intensity of "returning farmland to forests", a series of incentive measures have been introduced in a certain area: in the process of "returning farmland to forests", farmers whose forest land area reaches 10 mu every year and the forest land area increases every year can get a living allowance of 2,000 yuan in that year, each time exceeding 10. The following table shows the total annual income of a farmer in the first two years after returning farmland to forests: the total annual income per mu of forested land is 2002203 100 yuan and 2003265560 yuan (note: total annual income = living allowance+government reward+crop income) (1). Try to determine the values of a and b according to the above information. (2) Since 2003, if the newly-increased mu of forest land of this farmer grows at the same speed as that of the previous year, what will be the total income of this farmer in 2005? 28. (The full score of this small question is 10) A man was setting up a stall in the market to "touch the lottery". He saw a black bag in his hand, which contained 20 white balls with the same size, shape and quality, and the numbers (No.65438 +0-20) and 1 red balls were written on each ball. It is agreed to pay 1 yuan in advance, write a number within 1-20, and touch the Red Ball Award 5 yuan. If the number you touch is the same as the number you write, you will be awarded 10 yuan. Do you think this game is good for lottery winners? State your reasons. (2) If a lottery winner wins many prizes, how much will he earn or lose each time? 29. (Full score for this small question 10) It is known that the radius of the cone bottom surface r = 20 cm and the height h= cm. Now there is an ant starting from a point on the bottom edge. Crawl on the edge for a week and then return to point A to find the shortest distance for ants to crawl. As shown in the figure, in the plane rectangular coordinate system, the quadrilateral OABC is rectangular, and the coordinates of point A and point B are (6,0) and (6,8) respectively. Moving points M and N start from O and B at the same time, respectively, and move at the speed of 1 unit per second. Among them, point M moves along OA to endpoint A, point N moves along BC to endpoint C. Through point N as NP⊥BC, it crosses AC to P and connects MP. It is known that the moving point has moved for x seconds. The coordinate of point (1)P is (,); (expressed by an algebraic expression containing X) (2) Try to find the maximum value of ⊿MPA area and find the value of X at this time. (3) Please explore: When X is what value, ⊿MPA is an isosceles triangle? How many situations have you found? Write your research results. In 2009, the full-truth simulation test paper for the senior high school entrance examination answered: 1. 1,C; 2、C; 3、D; 4、A; 5、C; 6、B; 7、D; 8、B; 9、A; 10、B; Second, 1 1, 8; 2. and; 13、 ; 14, or; 15、6; 16, six; 17, rotation center and rotation angle; 18、9:30; 19、4; 20、5; 3. 2 1, original type =; When, the original formula =; 22. As shown in the figure, it is easy to calculate AE = 8m, from AC = 7m and CE= 1 m.. According to the ratio, CH= 1.5 m 1 m, which affects the lighting. 23、 1 1, 17,59; s = 6n- 1; 24 、( 1)y =—x2+2x+3; (2)x= 1,M( 1,4),(3)9; 25.( 1) Similarity: the heights of steps A and B are uneven, but the difference is that the height range of step A is smaller than that of step B; (2) step a, because the variance of the height of each step in step a is smaller than the variance of step b; (3) The smaller the variance of each step height, the better. 26 、( 1)r = 3; (2)3 < r < 4; (3)r=4 or 5; (4) r > 4 and r ≠ 5; 27. (1)a= 1 10, b = 90 Hint: It can be obtained from the solution; (2) As can be seen from the information in the table, the annual growth rate of newly-added forest land mu is 30%, so the forest land mu in 2004 was 26× (1+30%) = 33.8 mu, and in 2005 it was 33.8× (1+30%) = 43.94 mu. 28, (1)P (touch the red ball) = P (touch the ball with the same number) =; Therefore, it is not good; (2) The average income per time is 0, so the average loss per time is RMB. 29, 80 cm; Prompt: r=20cm, h=20 cm, bus l=80cm, the arc length of the sector after the expansion of the cone edge is, and the central angle of the sector after the expansion of the cone edge is 90, so the shortest distance is 80cm. 30 、( 1)(6—x,x); (2) Let the area of ⊿MPA be S, and the height on the side of ⊿MPA is X, where 0 ≤ x ≤ 6. ∴ S = (6-x) × x = (-x2+6x) =-(x-3)。 ② If MP = ma, MQ = 6-2x, pq PQ= x, pm = ma = 6-x, ∫ PM2 = Mq2+Pq2 ∴ (6-x) 2 = (6-2x) 2+(x) 2 in RT ∴ PMQ.