When the altitude rises 1000 meters, the temperature change is - 6 degrees Celsius. When the ground temperature is 0 degrees Celsius, if the mountain height is 4000 meters, the mountain should be calculated What's the temperature at the top?

When the altitude rises 1000 meters, the temperature change is - 6 degrees Celsius. When the ground temperature is 0 degrees Celsius, if the mountain height is 4000 meters, the mountain should be calculated What's the temperature at the top?

-24 degrees centigrade

X = a into polar equation, y = B into polar function process!

The Cartesian coordinates (x, y) of point P and its polar coordinates (P, w) (Note: P and W represent polar diameter and polar angle respectively) have the following quantitative relationship:
x=pcosw
y=psinw
According to this, we can transform x = a into the polar coordinate equation pcosw = a; y = B into the polar coordinate function psinw = B

It is known that B is the mean of the equal difference between a and a + B, and the mean of the equal ratio between a and AB, if 0

a +a+b=2b
a*ab=b＾2
It can be seen from the above two formulas that a = 0 (rounding) a = 2
∴b=4
ab=8>1
∵0

What is the main content of special relativity?

Four dimensional space time view of special relativity
Special relativity is a theory based on the four-dimensional space-time view. To understand the content of relativity, we need to have a general understanding of the space-time view of relativity. In mathematics, there are various multi-dimensional spaces, but so far, the physical world we know is only four-dimensional, that is, three-dimensional space plus one-dimensional time, There is no discussion here
Four dimensional space-time is the lowest dimension of the real world. Our world happens to be four-dimensional. As for the high-dimensional real space, at least now we can't perceive it. I said in a post that a ruler rotates in three-dimensional space (excluding time) with the same length, but when it rotates, its coordinate values change, The meaning of the four-dimensional space-time is that time is the fourth dimensional coordinate, which is related to the spatial coordinate, that is to say, space-time is a unified and indivisible whole, and they are a relationship of "one ebb and the other"
In four-dimensional space-time, mass (or energy) is actually the fourth dimension component of four-dimensional momentum. Momentum is the quantity describing the motion of matter, In addition, in the four-dimensional space-time, four-dimensional velocity, four-dimensional acceleration, four-dimensional force and four-dimensional form of electromagnetic field equations are also defined. It is worth mentioning that the four-dimensional form of electromagnetic field equations is more perfect, completely unifying electricity and magnetism, The electric field and magnetic field are described by a unified electromagnetic field tensor. The physical law of four-dimensional space-time is much more perfect than the three-dimensional law, which shows that our world is indeed four-dimensional. It can be said that at least it is much more perfect than Newton's mechanics. At least because of its perfection, we can't doubt it
In the theory of relativity, time and space form an inseparable whole - four-dimensional space-time, and energy and momentum form an inseparable whole - four-dimensional momentum. This shows that there may be a profound connection between some seemingly unrelated quantities in nature, There is also a deep connection between space-time and the four vectors of energy and momentum
Basic principles of special relativity
There is no matter that does not move and no matter that does not move in the interaction. Because matter moves in the interaction, it is necessary to describe the motion in the relationship of matter, not in isolation. That is to say, there must be a reference for motion, which is the reference system
Galileo once pointed out that the motion of a moving ship is indistinguishable from that of a stationary ship. That is to say, when you are in a closed cabin and completely isolated from the outside world, even if you have the most developed mind and the most advanced instruments, you can not perceive whether your ship is moving at a constant speed or still at a standstill. What's more, you can not perceive the speed because there is no reference, We don't know the whole motion state of our universe, because the universe is closed. Einstein cited it as the first basic principle of special relativity: the principle of special relativity. Its content is that inertial frames are completely equivalent and indistinguishable
The famous Michelson Morey experiment completely negates the ether theory of light and concludes that light has nothing to do with the reference frame. That is to say, whether you stand on the ground or on a running train, the measured speed of light is the same. This is the second basic principle of special relativity, the principle of constant speed of light
From these two basic principles, we can directly deduce all the contents of special relativity, such as the coordinate transformation and speed transformation. For example, the change of speed is contrary to the traditional law, but it is proved to be correct in practice. For example, the speed of a train is 10m / s, the speed of a person on the car is 10m / s, and the speed of a person on the ground is not 20m / s, It's about (20-10 ^ (- 15)) m / s. under normal circumstances, this relativistic effect can be completely ignored, but when approaching the speed of light, this effect increases significantly. For example, the speed of a train is 0.99 times the speed of light, and the speed of a person is 0.99 times the speed of light, so the ground observer's conclusion is not 1.98 times the speed of light, but 0.999949 times the speed of light, For him, it is also the speed of light. Therefore, in this sense, the speed of light can not be surpassed, because no matter in that reference frame, the speed of light is constant. The speed transformation has been proved by numerous experiments of particle physics, which is impeccable. Because of this unique property of light, it is selected as the only ruler of four-dimensional space-time
Effect of special relativity
According to the principle of special relativity, inertial frame is completely equivalent. Therefore, in the same inertial frame, there is a unified time, which is called simultaneity. Relativity proves that there is no unified simultaneity in different inertial frames, that is, two events (time and space points) are at the same time in one relative frame, and they may not be at the same time in another inertial frame. This is the relativity of simultaneity, The time course of the same physical process is exactly the same. If we use the same physical process to measure time, we can get a unified time in the whole inertial frame. In the future general relativity, we can know that space-time is not uniform in non inertial frame, that is to say, there is no unified time in the same non inertial frame, so we can not establish a unified simultaneity
Relativity deduces the relationship of time progress between different inertial frames. It is found that the time progress of moving inertial frame is slow, which is the so-called clock slow effect. It can be understood that the moving clock is slower than the stationary clock. Moreover, the faster the moving speed is, the slower the clock is going. When it approaches the speed of light, the clock almost stops
The length of a ruler is the difference between the coordinate values of two end points obtained at the same time in an inertial frame. Due to the relativity of "simultaneous", the length measured in different inertial frames is also different. Relativity proves that the ruler moving in the length direction of the ruler is shorter than the ruler at rest, which is the so-called scale effect. When the speed is close to the speed of light, the ruler shrinks to a point
Special relativity effect 2
From the above statement, we can see that the principle of clock slowness and ruler contraction is that the time progress is relative. That is to say, the time progress is related to the reference frame. This fundamentally negates Newton's absolute space-time view. Relativity holds that absolute time does not exist, but time is still an objective quantity. For example, in the twin ideal experiment to be discussed in the next issue, my brother will be 15 years old when he comes back from the spaceship, The younger brother may have been 45 years old, which indicates that time is relative, but the elder brother did live for 15 years, and the younger brother also confirmed that he lived for 45 years, which has nothing to do with the reference system, and time is "absolute". This shows that no matter how the object moves, the time it experiences is an objective quantity and absolute, which is called fixed time. In other words, no matter what form you move, You think that your coffee drinking speed is normal, your life is not disturbed, but others may see that you drink coffee for 100 years, and it takes only one second from putting down the cup to dying
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X (- x) ^ 2 (- x ^ 3) - 2x ^ 3 (- x) ^ 3 + 3x ^ 2 (- x ^ 4) =? Calculation problem

x(-x)^2(-x^3)-2x^3(-x)^3+3x^2(-x^4)
=x*x^2(-x^3)+2x^3x^3-3x^2x^4
=x^3(-x^3)+2x^6-3x^6
=-x^6-x^6
=-2x^6

As shown in the figure, four identical small rectangles and one small square are inlaid into a square pattern. The known area of the pattern is 49, and the area of the small square is 4. If x and y are used to represent the length of the two sides of the small rectangle (x > y), please observe the pattern and write three equations represented by X and y

∵ the area of the pattern is 49, the area of the small square is 4, the side length of the pattern is 7, the side length of the small square is 2, the countable equation can be as follows: x + y = 7, x = y + 2, (x + y) 2 = 49, (x + y) 2 = (2Y + 2) 2, (x + y) 2 = 4xy + 4 (choose any three)

When the rotational speed of the motor is constant, the rotational speed of the driven wheel W is the inverse proportional function of the ratio n of the radius of the driven wheel and the radius of the driving wheel. If the rotational speed of the driving wheel (that is, the motor) is 2800 rpm, the functional relationship between the rotational speed of the driven wheel W and the ratio n of the radius of the driven wheel and the radius of the driving wheel is written, What is the minimum ratio n between the radius of the driven wheel and the radius of the driving wheel?

w=2800/n;
N is at least 8

The number of a three digit number is 7. If the number of a three digit number is moved to the first place, the new number will be 86 times more than 5 times the original number. Find the three digit number, and let the first two digits of the three digit number be x, then the equation listed is ()
A.（700+x）\5-86=10x+7
B.700+x-86=5（10x+7）
C.（700+x)\5+86=x+7
D.5(700+x)=x+7+86

b

A rectangle is 100cm long and 75cm wide. How many square cardboard can be cut? (the side length should be as large as possible, and the length and width should not be left.)
How many square boards can you cut? What's the area of each board?

It can cut four square cardboard: one 75 × 75; three 25 × 25
Just draw a picture

Square divides a cube with an edge length of 10 cm into two cuboids of the same size. What is the surface area of each cuboid? The surface area formula of cuboid

Sum of surface area of two cuboids = surface area of cube + area of two cross sections
The surface area of the two cuboids is 10 × 10 × 6 + 10 × 10 × 2 = 800 square centimeters
The surface area of a cuboid is 800 △ 2 = 400 square centimeters
A: the surface area of each cuboid is 400 square centimeters