What is the relationship between indefinite integral and original function?

What is the relationship between indefinite integral and original function?

Generally, it can be considered that the obtained indefinite integral is the original function, but there are very few rare examples. The obtained indefinite integral needs a little continuous development to become the original function. For example, the indefinite integral of this function, 1 / (1 + x ^ 4), you can calculate its indefinite integral, and then you can find something when you go back

Add another number, that is, he and 0.16, 0.32, two fifths form a proportion. Write several if you can
It's the last question on page 14 of the second volume of the sixth grade

Given three numbers, any two multiply, and then remove to another one
0.16×0.32÷(2/5) = 0.128
0.16×(2/5)÷0.32 = 0.2
0.32×(2/5)÷0.16 = 0.8
All three above are OK

Let a be an M × n matrix and R (a) = R. it is proved that there exists an M × n matrix B with rank r and an R × n matrix C with rank r, such that a = BC

There is a little mistake in the title. The order of B is MXR, otherwise you can't multiply it casually
Let m-order invertible matrix P and n-order invertible matrix Q such that a = PDQ, where
D=
I_ r 0
0 0
Take B as the first R column of P and C as the first R row of Q

Of all the four digits whose sum equals 34 and can be divided by 11, the largest one is______ The smallest one is______ ．

Let the largest one of the four digits divisible by 11 be ABCD, ∵ a + B + C + D = 34, ∵ B + D - (a + C) is the smallest, that is, B + D = a + C = 17, so when a = b = 9, C = D = 8, the largest number is 9988, because 17 can only be divided into two digits, the largest number of 9, ∵ the smallest number is 8899

Let a be a third-order matrix, | a | = 2, and a * be the adjoint matrix of a, then the determinant | 3A ^ - 1) + 2A*|=____

A^-1=1/|A| x A* =1/2A*
So 1 / 2 = | a ^ - 1 | = | 1 / 2A * | = 1 / 8 | a * |, | a * | = 4
|3A^-1+2A*|= |3*1/2A*+2A*|=|7/2A*| =（7/2）^3 *4 = 343/2

Three times of a number is 20.4 less than seven times of it. What's the number? How to use the equation to solve it

HD nerve music,
Let this number be X
7X－3X＝20.4
4X＝20.4
X＝5.1

One third of China's land is threatened by desertification (mainly distributed in Xinjiang and Inner Mongolia, and a small number in Gansu, Qinghai and Ningxia). It seriously restricts the local economic development and affects people's living standards
Therefore, how should we correctly treat the problem of land desertification in China?
It is also related to the problem of sea level rise in the future. It is said that the sea level will rise by 4 meters. If it rises by 1 meter, many coastal cities in the world will be threatened, because the glaciers in the north and south poles are melting

Ecological scientific management

Xiao Li read a 96 page story book. On the first day, he read 1 / 6 of the whole book. How many pages did he read on the first day? If he read 1 / 4 of the whole book on the second day, it would take two days
How many pages did you read? If you read the remaining 1 / 4 the next day, how many pages did you read in two days? If you read 3 / 4 the first day, how many pages did you read in two days?

How many pages did you read in the first day? 96 × 1 / 6 = 16 (pages) if you read 1 / 4 of the whole book in the second day, how many pages did you read in two days? 96 × 1 / 4 + 16 = 24 + 16 = 40 (pages) if you read the remaining 1 / 4 in the second day, how many pages did you read in two days? 96 × (1-6 / 1) × 1 / 4 + 16 = 20 + 16 = 36 (pages) if

Given that a and B are rational numbers, m and N represent the integral part and fractional part of 5-7 respectively, and amn + BN2 = 1, then 2A + B = 1___ ．

Because of 2 & lt; 7 & lt; 3, so 2 & lt; 5-7 & lt; 3, so m = 2, n = 5-7-2 = 3-7. Substituting M = 2, n = 3-7 into amn + BN2 = 1, 2 (3-7) a + (3-7) 2B = 1 is reduced to (6a + 16b) - 7 (2a + 6b) = 1, and the two sides of the equation are compared, because the result does not contain 7, so 6A + 16b = 1 and 2A + 6B = 0, the solution is a

Passenger cars and freight cars leave from a and B at the same time. Passenger cars travel 60km per hour, and freight cars travel 1 / 15 of the whole journey per hour. When they meet, passenger cars travel more than freight cars
25%. How many kilometers is the distance between a and B?
The process should be detailed

The speed ratio of the two cars is 5:4
The speed of the truck is:
60 * (4 / 5) = 48km / h
The whole process is as follows:
48 * (1 / (1 / 15)) = 720km