The students are sitting in the broad reading room reading. Why should the broad be changed to spacious

The students are sitting in the broad reading room reading. Why should the broad be changed to spacious

Broadness generally refers to the open and unobstructed places, such as squares, fields and sky, while the reading room is obviously not, while spacious generally refers to the space in a closed or semi closed environment. Chengdu is generally used for classrooms, sports fields and so on, so it's right to replace it with spacious!

The students are sitting in the wide reading room reading

The students are sitting in the wide reading room reading books

The students are sitting in the wide reading room

The reading room should be bright

Chord length formula of circle
Angle 20 degrees, arc length 1.73 meters, chord length

First, use L = 20 and R / 180 = 1.73 to calculate the radius, and the radius R is about 5
Then the chord length can be obtained by cosine theorem
D = under root sign (2R ^ 2-2r ^ 2cos20) = 1.73
Because the angle is very small and the radius is very long, the field is almost equal to the arc length, but the chord must be shorter than the arc

The monthly income ratio of the two brothers is 7:5, and the expenditure ratio is 3:2. Each of them has a monthly savings of 200 yuan. How much is the total monthly income of the two brothers? (it's better to have a solution or analysis process)

It can be done by solving the proportion
The monthly income of the two brothers is 7x yuan and 5x yuan respectively, and they both save 200 yuan
Therefore, they spend 7x-200 yuan and 5x-200 yuan per month
(7x－200)/(5x－200)＝3/2
The solution is: x = 200
Thus, the monthly income of the two brothers is 7 × 200 = 1400 yuan and 5 × 200 = 1000 yuan respectively, a total of 2400 yuan

Given that the solution of the equation 2x + a = X-6 is x = 6, find the value of 3a-9

Take x = 6 into 2x + a = X-6 to get
12+a=6-6
12+a=0
a=-12
3a-9
=3×(-12)-9
=-36-9
=-45

There is 10cm deep water in a cylindrical tank, and the bottom area is 400cm2. If a square iron block with 10cm long edge is put into the tank, how much will the water surface rise?

The volume of cube is 10 × 10 × 10 = 1000 cubic centimeter
1000 △ 400 = 2.5cm

1. Write two words similar to the following words
(1) Hot, stiff__________
(2) Sweet honey__________
(3) White, white, round, round__________
(4) Famous at home and abroad, attracting worldwide attention__________
2. Follow the example sentences and complete them
In the dark blue sky, the twinkling stars blink like naughty children
(1) The red maple all over the mountain is just like______________________________ .
(2) The beautiful sound of spring on Dinghu Mountain______________________________ .
(3) The sun is shining on the surface of the sparkling Lake as if it were______________________________ .
(4) The hundred meter waterfall is like a waterfall______________________________ .

(1) Cold, soft
(2) Soft and cool
(3) Clean up and walk around
(4) The world is famous
(1) The red maple all over the mountains is burning like a raging fire
(2) The beautiful sound of the spring on Dinghu Mountain is just like the sound of a musical instrument
(3) The sun shone on the surface of the sparkling lake like twinkling stars
(4) The hundred meter waterfall is like the Milky way in the universe

Given that the domain of the function y = f (x-1) is [0,2], then the domain of F (AX) + F (x / a), (a > 0) is

x-1€[0,2]；
x€[1,3]；
F (x / a) + F (AX) is defined as {x | X & # 8364; [a, 3A]} and {x | X & # 8364; [1 / A, 3 / a]};
So it can be divided into a

Let f = [sin (2 / x)] = 1 + cosx, find f (x), f [cos (2 / x)]
As the title!

cosx=1-2(sinx/2)^2
f=[sin(2/x)]=1+cosx=2-2(sinx/2)^2
f(x)=2-2x^2
f[cos(2/x)]=2-2[cos(2/x)]^2