The differential of integral of function f (x) on interval [0. X]

The differential of integral of function f (x) on interval [0. X]

d[∫(0→x)f(x)dx]=f(x)dx

Is the value of the function multiplied by a constant in the differential equation? Can we move this constant out of the equation? For example: DCF (x) / DX, C is a constant
It can be equal to DCF (x) / DX = CDF (x) / DX
Specific example: d2x / DX = 2DX / DX = 1
Is that understandable?

Yes. It can be understood in this way. Constants can be put aside first. If you have any questions, please ask me again~

Xiao Hua read a book. On the first day, he read 18 pages more than 21, and on the second day, he read 16 pages less than 6, with 172 pages left. How many pages are there in this story book?

Suppose there are x pages in this story book, the number of pages read on the first day: 18x + 21, the number of pages read on the second day: 16x-6, X - (18x + 21) - (16x-6) = 172, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X -- 18x-21-16x + 6 = 172, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

When Wang Ming calculated the difference of a polynomial minus 2B & # 178; - 3b-5, he forgot to enclose the two polynomials in brackets for a moment, so the two terms after the subtraction did not change sign. The result is B & # 178; - 3b-1. Based on this, can you work out the polynomial and calculate the result?

Let this polynomial be a, then the original formula is a - (2B & # 178; 10 B-5), but Xiao Ming wrote a - 2b & # 178; 10 B-5, and the result is B & # 178; - 3b-1. Therefore, there is the following formula a - 2b & # 178; 10 B-5 = B & # 178; - 3b-1. Therefore, a number of a = 3B & # 178; - 4B + 4 should have been calculated

The distance between a and B is 80 kilometers. A bus goes from a to B, and a car goes from a to B one hour later,
Its speed is three times that of the bus. As a result, the car arrived at the second place 20 minutes earlier than the bus,

The distance between a and B is 80 km. A bus goes from a to B. an hour later, a car goes from a to B. the speed is three times as fast as the bus. As a result, the car arrives at B 20 minutes earlier than the bus

How to draw the number axis

Draw a straight line, add an arrow to the right, mark a zero point in the middle, and then mark the number equidistant on both sides... - 10 1 2 3

An express train from city a to city B runs 65 kilometers per hour, and a bus from city B to city a runs 60 kilometers per hour at the same time. The two trains meet at 20 kilometers in the middle of the drama. How many kilometers is the distance between the two places?

(20 + 20) / (65-60) x (65 + 60) = 1000 km
The two trains meet at 20 km in the middle of the drama, and the surface express train runs 20 + 20 = 40 km more than the full train
Fast trains travel 65-60 km more per hour than local trains
The driving time of two vehicles is 40 △ 5 = 8 hours
Speed and 65 + 60 = 125 km
Distance = 125x8 = 1000km

The power of 20 - the power of 19 + the power of 18 - the power of 17 + The second power of 2 - the second power of 1 =?

The power of 20 - the power of 19 + the power of 18 - the power of 17 + The second power of 2 - the second power of 1
=(20+19)*(20-19)+(18+17)*(18-17)+^+(2+1)*(2-1)
=20+19+18+17+…… +2+1
=（20+1)*20/2
=210
That's all

When the radius of uniform circular motion is R and the acceleration of gravity is g, the effect of air on the aircraft is?
Let the resistance of the river be proportional to the square of the ship's speed. If the ship's speed of uniform motion is twice of the original, the power of the ship will be several times of the original

The effect of air on aircraft is that the resultant force of Mg and MV ^ 2 / R is m root sign (G ^ 2 + V ^ 4 / R ^ 2)
2.p=fv
The river resistance is proportional to the square of the ship's speed,
The power of the ship has increased eight times

Let the eccentricity of the ellipse be half, the right focus be f (C, 0), and the two real roots of the equation AX + bx-c = 0 be x1, X2, then p (x1, x2)
A: It must be in the circle x + y = 2
B: It must be on the circle x + y = 2
C: It must be outside the circle x + y = 2
(multiple choice)

Choose a
∵ right focus f (C, 0) and E = 1 / 2
∴a=2c b=√3c
The elliptic equation is
x²/(4c²)+y²/(3c²)=1
(x1)²+(x2)²=(x1+x2)²-2x1x2
According to Veda's theorem
x1+x2=-b/a
x1x2=-c/a
∴(x1)²+(x2)²=3/4+1=7/4