The good news spread to the school

The good news spread to the school

New machines make parts day and night. 1. Good news comes to school. 2. The train goes through the valley. 3. The spring breeze blows all over the earth

The library bought three bookshelves, each of which has four layers. Each layer can hold 350 books. How many books can these bookshelves hold?

3 × 4 × 350 = 4200 copies

Given a (- 1, - 2) and B (1,3), the______ Translation______ The point B is symmetric about the Y axis

According to the law of symmetrical points in the plane rectangular coordinate system, the point B is symmetrical about the y-axis (- 1,3), and the point a (- 1, - 2), so the point (- 1,3) is obtained by translating the point a upward five unit lengths

The function f (x) = Sina ω x, (ω greater than 0) has f (π / 3-x) = f (π / 3 + x) for any x, then f (π / 3) is equal to ()

∵f(π/3-x)=f(π/3+x)
The symmetry of F (x) with respect to the line x = π / 3
∵f(x)=sinawx
When this function x takes the axis of symmetry, f (x) is the maximum
Ψ f (π / 3) = 1 or - 1

6. If y = f (x) is a decreasing function in the interval (a, b), then the following conclusion is correct. Please explain the reason
6. If y = f (x) is a decreasing function in the interval (a, b), then the following conclusion is correct
A. Y = 1 / F (x) is a decreasing function in the interval (a, b)
B. Y = - f (x) is an increasing function in the interval (a, b)
C. Y = | f (x) | ^ 2 is an increasing function in the interval (a, b)
D. Y = | f (x) | is an increasing function in the interval (a, b)

This kind of problem had better use special value method, such as y = - x, interval (- 1,1), it is easy to exclude a C D

The equation of the line with intercept 3 on Y axis and parallel to the line 2x + y + 19 = 0 is_______

If the intercept of Y axis is 3, the linear equation can be written as y = KX + 3
The slope of the line 2x + y + 19 = 0 is - 2
So k = - 2, the linear equation is y = - 2x + 3

How to calculate 2.33 × 0.25 × 4

First 4 × 0.25

Find 60 problems in the calculation of binary linear equations and inequalities in grade one mathematics. The difficulty is medium or low! Don't use too long formula. You can copy other people's

3 (y-2x) + 4Y = 2x + 19 2x + 5Y = 292. 3M + 2n = 20 4m-5n = 193. (2x + 3Y) △ 4 + (2x-3y) △ 3 = 6 (2x + 3Y) △ 3 + (2x-3y) △ 2 = 84. (2x + 3Y) △ 4 + (2x-3y) △ 3 = 12.55 ^

As shown in the figure, the parabola y = - 1 / 4x ^ + X + 3 intersects the x-axis at two points a and B, intersects the y-axis at point C, and finds the analytical formula of the straight line BC
Well, I'd better draw the picture myself,

C coordinate is (0, Y1)
Take Y1 into the parabola and get C (0,3)
When y = 0
0=-1/4X^+X+3
The solution is X1 = 6, X2 = - 2
If a is to the left of B, then B (6,0)
BC: x + 2y-6 = 0 with B, C coordinate solution
If B is to the left of a, then B (- 2,0)
Similarly, BC: 3x-2y + 6 = 0

Given that f (x) = 2cos (3x - π / 6), the equation of symmetry axis of F (x) image is obtained. When x ∈ [0, π / 3], the maximum and minimum of F (x) are obtained

Let 3x - π / 6 = k π, the equation of axis of symmetry is x = k π / 3 - π / 18
x∈[0,π/3] (3x-π/6)∈[-π/6,5π/6] cos(3x-π/6)x∈[-√3/2,1]
2cos(3x-π/6)x∈[-√3,2]
So the maximum value of F (x) is 2 and the minimum value is - √ 3