When an inequality with X has a negative number on the other side and a positive number on the other side, does the sign change

When an inequality with X has a negative number on the other side and a positive number on the other side, does the sign change

Yes, the symbol needs to change direction

How to pronounce w in pinyin

5、 For example, wow, five "wow"

The formula of eight symmetries in high school mathematics

1) Point about point symmetry: Idea: using the midpoint coordinate formula, point a (a, b) about the origin symmetry point a '(- A, - b). (2) point about the straight line symmetry: ① point a (a, b) about the X axis symmetry point a' (a, - b). ② point a (a, b) about the Y axis symmetry point a '(- A, b). ③ point a (a, b)

There are four operations of decimals, which need to be simplified. (10 lines)
Fifth grade!! Urgent!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

41×101
907×99+907
56×99
4.06－2.8－0.7
1200-197
95.6×18+0.4×18
16÷2,5
0.7+4.9+5.3+6.1
（0.125×8―0.5）×4
1+0.45÷0.9－0.75

Equation x / 1 × 2 + X / 2 × 3 + X / 3 × 4 + +The solution of X / 2007 × 2008 = 2007

Simplification of the original formula
x(1/1-1/2 1/2-1/3. 1/2007-1/2008)=2007
x(1-1/2008)=2007
2007x/2008=2007
x=2008
Hope to help you ^ o^

Find the maximum area s of the inscribed rectangle of the ellipse x ^ 2 + 4Y ^ 2 = 8 and the coordinates of the four vertices of the rectangle

Suppose a point is (m, n), where m > 0, n > 0
Then the other three points are (m, - n), (- m, - n), (- m, n)
So the side length is 2m, 2n
That is to find the maximum value of Mn
m>0,n>0
m²+4n²=8
8=m²+4n²>=2√(m²*4n²)=4mn
4mn

Do not change the order of 1, 2, 3, 4, 5, add the operation symbol, so that the calculated number is 10
The existing formulas are (1 + 2) △ 3 + 4 + 5 = 10, (1 + 2 + 3-4) × 5 = 10, (1 + 2) × 3-4 + 5 = 10, (1 × 2 × 3-4) × 5 = 10

1+2+3×4-5=10

Given that a > 0, f (x) = - 2acos (2x + π / 6) + 2A + B, when x ∈ (- π / 4, π / 4), - 5 ≤ f (x) ≤ 1. (1) find the values of constants A and B
(2) Let g (x) = f (x + π / 4) and satisfy LG [g (x)] > 0, find the monotone interval of G (x)

(1) Because x ∈ (- π / 4, π / 4), 2x + π / 6 ∈ (- 2 π / 3, 2 π / 3)
So we get 2acos (2x + π / 6) ∈ (- 1 / 2,1],
a> When 2acos (2x + π / 6) = - 1 / 2, f (x) max = 1 = - 2A * (- 1 / 2) + 2A + B, a + B = 1
When 2acos (2x + π / 6) = 1, f (x) min = - 5 = - 2A * 1 + 2A + B, B = - 5
A + B = 1, B = - 5, so a = 6
（2）g（x）=f（x+π/4）=-2*6cos(2（x+π/4）+π/6)+2*6-5=-12cos（2X+2π/3）+7
Because x ∈ (- π / 4, π / 4), so 2x + 2 π / 3 ∈ (π / 6,7 π / 6)
G (x) decreases monotonically on (π / 6, π) and increases monotonically on [π, 7 π / 6]
Because we consider that LG [g (x)] > 0 = LG1, lgx is monotonically increasing in the domain of definition,
So we get: G (x) > 1, - 12cos (2x + 2 π / 3) + 7 > 1, cos (2x + 2 π / 3)

The number of solutions of the equation sin π x = 14x is______ ．

In the same coordinate system, make the images of y = sin π X and y = 14x, as shown in the figure: because the images of y = sin π X and y = 14x have seven intersections on [- 4,4], and when x ＜ - 4, or & nbsp; X ＞ 4, there will be no intersection between the two curves, the number of solutions of the equation sin π x = 14x is 7, so the answer is: 7

What does Jamie mean

Jamie:
1. Simple millet
2. It's Jane. It's Mel
3. The erhuayin of the name "Jianmi"
4. Net name or blog name