0 1. True question:
02. Reference answer:
Multiple choice questions 1-8 CDAACBDC
9.
The monotonically increasing interval is [0, 1] [2, -oo], and the monotonically decreasing interval is (one o, 0) Li (1, 2); The maximum value is 2 and the minimum value is 1.
Because f(z)=4a- 12'+8z=0, z=0 or z = 2, and f'(z)≥0, it is deduced that [0, 1] and [2, +oo] are monotonically increasing, and f'(z).
10.
2x-3y-z+7=O
a +y— z=0
B: inward direction m = (1, 1,-1); L2: inward direction m2 =(2, 1, 1), let the plane normal vector be
2r+y+z=o '
Let y = 1, then a =-', z=, and deduce n=(-, 1,) and since l is in the plane,
So the point (1, 2,3) is also in the plane, which leads to (z- 1)+(-2)+, (z-3)=0, that is, 2z-3g-z+7 = 0.
1 1.
( 1)0.84 ? (2)4/7。
Suppose there are 0.4 boys and 0.6 girls in this class, the probability of choosing a boy to skate is 0.36, and the probability of that person skating is 0.48.
The approximate macro of is ∩84 0.48_4.
Then the probability that the student chooses skating is 0.84 and 0.84 "7.
12.
Reference analysis: two methods to study the geometric properties of ellipses;
① Using curve equation to study geometric properties, such as studying the range of X and Y, the range of path and focal radius through elliptic equation, can explain the geometric meaning of elliptic standard equations A, B and C. This method is a model of mathematical thinking method combining numbers with shapes.
② Using algebraic method to study geometric properties. In the research process, the general method of studying geometric properties by algebraic method is extracted by intuitively abstracting the process of geometric properties from graphics, and the eccentric model is established.
13.
On the left side of the inequality (1) is the distance from (x, y) to (0,0), (o, 1), (1, 1), which can improve students' understanding of the distance formula between two points.
(2) The sum of the distances from (x, y) to these four points can be analyzed by combining the positions of these four points on the plane. The range of xy corresponds to the square range with the side length of the first quadrant of 1. In the process of solving this problem, students' ability of combining numbers and shapes has been improved.