Rescue, a question, the master can do it casually 20

Your score is too low and it's still a very important technical issue.

A circle with a radius of 50 cm occupies 1 meter square, and 8*4=32 meters square, so a maximum of 32 circles can be cut.

Answer: 1, Xiaoqiang reached the finish line first.

2, Xiaogang is first fast and then slow.

3. Xiaogang led at the beginning of the race, and Xiaoqiang took the lead after the start of the race, and the distance between the two was about 120 meters.

Analysis: 1, the dotted line represents Xiaogang, and the solid line represents Xiaoqiang. As can be seen from the image, Xiaoqiang reached 800 meters in the time, and Xiaogang only reached 800 meters in the time.

2. As can be seen from the image, the dotted line is first on the top, indicating that Xiaogang first ran faster than Xiaoqiang, and then at about 3 minutes and 15 seconds, that is, the dotted line and the solid line began to cross, and the solid line began to be on top, which means that Xiaoqiang gradually surpassed Xiaogang, so Xiaogang was first fast and then slow.

3. From the analysis of 2, it can be seen from the image that because Xiao Gang is first fast and then slow, Xiao Gang took the lead at the beginning of the game, and Xiao Qiang surpassed Xiao Gang at about 3 minutes and 15 seconds after the start, and then Xiao Qiang began to lead.

At 4 and a half minutes, the distance between the two lines is the largest, which means that Xiaoqiang reaches 800 meters, while Xiaogang only reaches about 680 meters, and the distance between the two lines in other places is smaller than this, so the distance between the two is about 120 meters at most.

Jack bauer. Fast and slow.

Xiaogang 3 Xiaoqiang 100

Answer: (1).

a+b+c=0, then a+b=-c,a+c=-b,b+c=-a, the equation is found = (-c)*(a)*(b) abc=-1(2) if a+b+c≠0, from the proportional property: a b+c=b c+a=c a+b=(a+b+c) (2a+2b+2c)=1 2

a+b=2c,b+c=2a,a+c=2b, the equation = (2c)*(2a)*(2b) abc=8 is the equation = -1 or 8

Answer: If abc≠0 and (a+b) c=(b+c) a=(c+a) b let (a+b) c=(b+c) a=(c+a) b=k, then there is:

a+b=kc

b+c=ka

c+a=kb

The above three formulas are added together:

2(a+b+c)=k(a+b+c)

k-2)(a+b+c)=0

Solution: k=2 or a+b+c=a+ka=(k+1)a=0 because: abc≠0

So: k=2 or k=-1

So: (a+b)(b+c)(c+a) abc=kc*ka*kb (abc).

k 38 or -1

3 symmetrical rotations. a=b=c

So the answer is 8

Solution: 1. Subtract the two inequalities (the second minus the first) to get 22, multiply the first inequality in the original inequality by 2 to get: -2<2a+2b<2 and then subtract the second inequality in the original inequality group to get: -3

According to the inscription, the Greek letters are not easy to type, so they are replaced by a, b, 2<=2a+4b<=6, and -1<=a+b<=1 are subtracted.

1<=a+3b<=7

Adding the two formulas gives greater than 0 and less than 4

(1) The degree of c does not change, c=45°.

If oab=x is set in the right-angle aob, then oba=90°-x, ban=180°-x, abm=180°-(90°-x)=90°+x, and because ac and bc are the angular bisectors of ban and abm, respectively, cab= ban 2=(180°-x) 2, cba= abm 2=(90°+x) 2, then c=180°- cab- cba=180°-(180°-x) 2-( 90°+x) 2=45°, so the degree of c does not change, c=45°.

2) The conclusion in question (1) is also true, the degree of c does not change, and c=45°.

If oab=x is set in the right-angle aob, then oba=90°-x, ban=180°-x, and because ac and bc are bisectors of the angles of ban and abo, respectively, cab=180°-(180°- oab) 2=(180°+x) 2, cba= abo 2=(90°-x) 2, then c=180°- cab- cba=180°-(180°+x) 2-(90°-x) 2=45° in abc, So the degree of c does not change, c = 45°.

This problem is a problem of solving the angle of a triangle in middle school mathematics. To answer this kind of question, we should pay attention to finding the unchanging conditions in the changing conditions. The key entry point for the solution of this problem is that the angle o is a right angle, so the triangle AOB is a right triangle.

When answering this question, it is necessary to grasp this condition firmly and make use of it. The detailed answer to this question is shown in the figure below.