If the differential of F (x) is cos2xdx, which of the following functions may be f (x) () A.sinxcosx B.sinxcosx+2 C.1/2sin2x D.1/2sin2x

If the differential of F (x) is cos2xdx, which of the following functions may be f (x) () A.sinxcosx B.sinxcosx+2 C.1/2sin2x D.1/2sin2x

All four,

On the differential understanding of function y = f (x)
If the function y = f (x), Dy is not the derivative of the function, is not f '(x), then why dy = f' (x) DX? What is DX?

Dy is the differential of Y, not the derivative of Y. Dy and f '(x) are not the same thing. Dy / DX is the derivative of Y and is equal to f' (x), so dy = f '(x) DX
DX is the differentiation of X

F (x) is the original function of F (x), G (x) is the original function of 1 / F (x), G (x) f (x) = - 1 f (0) = 1 to find the ordinary differential of F (x)

F '(x) = f (x) g' (x) = 1 / F (x)
Because g (x) = - 1 / F (x), the derivation is g '(x) = the square of F' (x) / F (x)
That is: 1 / F (x) = the square of F (x) / F (x)
So f (x) = the x power of E

In the isosceles trapezoid ABCD, EF is the median line, BD bisector angle ABC intersects EF at g, eg = 5, GF = 9, and the circumference of the isosceles trapezoid ABCD is calculated

Because BD bisects angle ABC, so angle abd = angle DBC, because AD / / BC / / EF, so angle DBC = angle DGF = angle ADB, and angle DGF = angle Bge (equal to vertex angle), so angle EBG = angle EGb, so eg = BG = 5, because EF is the median line, so AE = be = 5, so AB = 10, because isosceles trapezoid, so AB = DC = 10

Fill in the operation symbols +, -, ×, △, () to make the equation hold 5 5 15 = 8 3 8 3 = 24

5×(5-1÷5)=24
8÷(3-8÷3)=24

Given that the eigenvalues of a matrix of order 3 are 0, - 2,3 respectively, and the matrix B is similar to a, then | B + e | =?

The eigenvalues of B + e are 0 + 1, - 2 + 1, 3 + 1
That is: 1, - 1,4
∴|B+E|=1×(-1)×4=-4

A three digit number. The sum of your numbers is 24. How many three digits are there?

From a + B + C = 24,
7 + 8 + 9 = 24, (1)
8+8+8=24,（2）
6+9+9=24,（3)
Six three digit numbers are combined by (1): 789798879897987978,
From (2) to 888,
From (3), there are three 69996,
A total of 10

Let a be a real symmetric matrix of order n, and a ^ 2 + a-3e = 0, d = 1 be the single eigenvalue of a, then calculate the value of determinant a + 2E

Because a ^ 2 + a-3e = 0
So the eigenvalue of a satisfies λ ^ 2 + λ - 3 = 0
Isn't the title right

In a school, the number of girls in Grade 6 is 3 / 4 of that of boys, while the number of boys is 18 more than 2 / 5 of the total number, the equation is as follows

X people in total
(2/5X+18)×(1+3/4)=x
7/10x+63/2=x
x=105

2011 power of junior high school mathematics 3-2010 power of junior high school mathematics 3

2011 power of 3 - 2010 power of 3
=3²º¹¹-3²º¹º
=3²º¹º×(3-1)
=2×3²º¹º