To find the differential D (Xe ^ x), there is also a derivative (e ^ x) "

To find the differential D (Xe ^ x), there is also a derivative (e ^ x) "

d（xe^x)=(e^x+xe^x)dx.
（e^x)''=e^x

Derivative and differential of y = x|x|

y=x|x|=x² x>0
0 x=0
-x² x0
0 x=0
-2x x

F (x, y) = sin (XY), find FX (x, y) =?

This is the partial derivative of F over X,
In this case, y is regarded as a constant term
The original formula = ycos (XY)

As shown in the figure, two points a and B are on the number axis, and the corresponding number of point a is 2. If the length of line AB is 3, the corresponding number of point B is ()
A. -1B. -2C. -3D. -4

According to the number axis, we can see that B ＜ 0, a ＞ 0, and the number corresponding to B point is 2-3 = - 1

As shown in the figure, in order to measure the distance between two points a and B on the opposite bank of the river, CD = 32km, ∠ ADB = ∠ CDB = 30 °, ACD = 60 °, ACB = 45 ° are measured on this side of the river to calculate the distance between two points a and B

Ad = DC = AC = 32, in △ BCD, ∠ DBC = 45 °, ｜ bcsin30 ° = dcsin45 ° BC = 64, in △ ABC, according to the cosine theorem AB2 = ac2 + bc2-2ac · bccos 45 °, ｜ AB = 64 A: the distance between a and B is 64km

The sum of the internal angles of a triangle is equal to 180 degrees. It is known that the first internal angle of a triangle is equal to three times of the second internal angle, and the third internal angle is 15 degrees larger than the second internal angle. What is the degree of each angle?

Let the second internal angle be x, the first internal angle be 3x, the third internal angle be x + 15 °, the sum of internal angles of ∵ triangle be 180 °, and the solution be x = 33 °, the first internal angle be 3x = 99 °, the second internal angle be 33 ° and the third internal angle be 48 °

How many cubic meters is 5000 cubic meters!

How many ten thousand cubic meters is 5000 cubic meters? Or how many ten thousand cubic meters?
5000 m3 = 5000 M3
5000 cubic meters = 5 × 10 (- 9) cubic meters

The speed ratio of the bus to the truck is 3:2. What is the distance between a and B?

A: the distance between a and B is 450 km

The third power + 1 of X and the square + X ratio of X

Make a difference:
(x^3+1)-(x^2+x)
=(x+1)(x^2-x+1)-x(x+1)
=(x+1)(x^2-2x+1)
=(x+1)(x-1)^2
When x ＞ - 1 and not equal to 1, (x + 1) (x-1) ^ 2 > 0, that is: x ^ 3 + 1 > x ^ 2 + X
When x ＜ - 1, (x + 1) (x-1) ^ 2 ＜ 0, that is: x ^ 3 + 1 ＜ x ^ 2 + X
When x = - 1 or 1, (x + 1) (x-1) ^ 2 = 0, that is: x ^ 3 + 1 = x ^ 2 + X

5x+3（x-2）=15.6

5x+3（x-2）=15.6
5x+3x-6=15.6
8x=21.6
x=2.7