There are two cars a and B on the straight road. A starts to drive from a standstill at an acceleration of 0.5m/s2, and B moves at a constant speed in the same direction at a speed of 5m / s 200m in front of A. question: (1) when will a catch up with B? How fast does a catch up with B? How far is a from the starting point? (2) In the process of catching up, when is the maximum distance between a and B? What is the distance?

(1) When a overtakes B, the difference of their displacements is x0 = 200m, & nbsp; x a = x0 + X B. let a overtake B with time t, then x a = 12a a T2, x B = v b T. according to the condition of pursuit, there is 12a T2 = v b t + 200, and the solution is t = 40 & nbsp; s or T = - 20 & nbsp; s (omit)

Xiaoming and Xiaohua are running on the circular track. It takes 8 minutes for Xiaoming to run a lap and 10 minutes for Xiaohua to run a lap. Now it takes at least a few minutes for them to meet for the first time after they start from the starting point at the same time?

It takes at least 409 minutes for them to meet for the first time

Mathematics test paper of the first monthly examination in the first volume of 2011
Xi'an Xingzhi middle school,

I don't know yet. I won't know until I finish the exam
You can only understand the problems in the exercise books and textbooks. You'd better ask the teacher to give you more questions
Only in this way can we do well in the exam
I'm going to take the monthly exam, just like you. Let's work hard together. Now I'm looking for a topic to exercise myself
Come on, O (∩)_ ∩)O~

A point whose coordinate is an integer on the number axis is called integral point. The unit length of a certain number axis is 1cm. If a line segment AB with length of 2008cm is randomly drawn on the number axis, how many integral points are covered by the line segment AB

2008 or 2009

During the war of resistance against Japan, in a battle, our army and the enemy blockhouse across the river, in order to blow up the blockhouse, we need to know the blockhouse and our army
When the distance between the ground and the river is not measured, there is no measuring tool. A soldier came up with such a way: he stood facing the fort, then adjusted his hat, so that his line of vision fell right down the bottom of the fort, and then he turned an angle to protect his posture. He measured the distance between himself and that point, which is the distance between him and the blockhouse
Is this soldier's method reasonable? Please draw a picture and explain the reason with a picture

Theoretically, it is reasonable, but in fact, the error is very large. A soldier is equivalent to drawing a circle around his position and taking his distance from the enemy blockhouse as the radius. Because his eyes are in the same straight line with the brim and the bottom of the enemy blockhouse, the intersection of the brim of his eyes and his position is a rotating projection of the enemy blockhouse in our army

The more examples of integral addition and subtraction, the better

1.2xy+5x^2y+3xy+45x^2y
=2xy+3xy+5x^2y+45x^2y
=5xy+50x^2y

Divide 1-999 into 20 groups. It is known that the average number of each group in the 20 groups is equal, and the equal average number is______ ．

(1 + 999) × 999 ／ 2 ／ 999, = (1 + 999) ／ 2 = 1000 ／ 2, = 500

A passenger car and a freight car run from both sides of a and B at the same time and meet at a distance of 30km from the midpoint. The speed ratio of the passenger car and the freight car is 5:4. How many km does the freight car travel when they meet?

Suppose the freight car runs a kilometer when meeting, then (a + 30 * 2): a = 5:4, 5A = 4A + 60 * 4, a = 240 (km)

It is known that the function y = (m-2) x3-m2 is an inverse proportional function (1) when - 3

3-m2=-1
m=±2
And because m ≠ 2
So y = - 4 / X
When - 3 ≤ x ≤ - 1 / 2, 4 / 3 ≤ y ≤ 8
The maximum value is 8 and the minimum value is 4 / 3

How to solve the problem of 5x / 2 = 5 / 6 + 4x / 7 = 5 / 3 - 3x / 4
The first question is 7 / 12 / 6 / 7 × 4 / 5; the second question is 5 / 4-9 / 36 / 5; the third question is 3 / 1-8 + 1 / 4 / 16 / 15
1 / 5 of the fourth question [(7 / 9-2 / 3) × 1 / 4] 4 / 5 of the fifth question 238 / 239 of the sixth question

The first question: 7 / 12 / 6 / 7 × 4 / 5 = 7 / 12 × 6 / 7 × 4 / 5 = 2 / 5
Question 2 (5 / 4-9) △ 5 / 36 = 31 / 9 × 36 / 5 = 124 / 5
Question 3 (3 / 1-8 + 1 / 4) △ 15 / 16 = 7 / 8 × 16 / 15 = 14 / 15
Question 4: 1 / 5 △ [(7 / 9-2 / 3) × 1 / 4] = 1 / 5 △ [1 / 9 × 1 / 4] = 1 / 5 × 36 = 36 / 5
Question 5: 4 of 7 and 5 △ 4 of 5 and 7 = 39 / 5 × 4 / 39 = 4 / 5
Question 6 238 / 239 = 238 × 239 / 238 = 239