The first semester entrance examination of 2009-20 10 school year in eight schools.
Proposition teacher: Xiaonan experimental middle school Chinese.
Choose carefully first, and then make a final decision (this big question * *, a total of 12 small questions, 3 points for each small question, out of 36 points). For each small question, give four answers, one of which is the correct answer. )
1. Quadratic root number 12, root number x? +3, root one third, root a? B, the quadratic root number is 0.5, the root number is 26, and the probability of the simplest quadratic root is
a . 1/6 b . 2/3 c . 1/2d . 1/3
(Because the multiple-choice questions are very simple, some pictures are difficult to draw, so I won't send them. )
2. Fill in the blanks patiently and accurately (this topic is entitled ***6 small questions, with 3 points for each small question, with a full score of 18).
13. If (root number-x)/(absolute value of x-3) is meaningful, then the value range of x is _ _ _ _ _.
14. If x+ 1/x= root number 1 1, then x- 1/x = _ _ _ _ _.
15 simple
16. If a square dining table with a side length of 60cm is covered with a circular tablecloth with a radius of R, the minimum value of R is _ _ _ _ _ _.
17 and 18 are difficult to draw.
Three. Answer carefully, and be brilliant (out of 66 points for seven small questions in this big question)
19.( 1) Calculation (2) Solving the equation is simple. If you don't send it, just look it up online.
20 questions are probability questions, and they are relatively simple, so I won't find them online.
2 1 is a question about rotation, which was found online.
22.( 10 points) It is known that the equation X is about X? -(k-2)x- 1/4 k？ =0
(1) It is proved that no matter what the value of k is, the quadratic equation always has two unequal real roots.
(2) The two real roots x 1 and x2 of the quadratic equation satisfy |x 1|=|x2|+2, and find the value of k. ..
23. (The full mark of this question is 10) As shown in the figure, AB is the diameter of the circle O, BC is the chord, OD⊥BC is in E, and the intersection BC is in D.
(1) Please write three different types of correct conclusions;
(2) If BC=8 and ED=2, find the radius of circle O. ..
24.( 10) Watermelon business owners buy a batch of small watermelons at the price of 2 yuan/kg and sell them at the price of 3 yuan/kg, which can sell 200 kg a day. In order to promote sales, the business owner decided to reduce the price. After investigation, it was found that every time the price was reduced by 0. 1 yuan/kg, this small watermelon could sell 40 kg more every day. In addition, the daily rent and other fixed costs ***24 yuan. If business owners want to make a profit in 200 yuan, how much will the price of small watermelons be reduced per kilogram?
I can't draw this question, but I can't draw it well, so I didn't send it. This is a combination of coordinates and circles. )