The circumference of a square is 36 cm, and its side length is______ Cm

36 △ 4 = 9 (CM). A: its side length is 9 cm. So the answer is: 9

Simplification of positive and negative numbers
+(- 4); - (- 5 and 1 / 2));
-[+ (- 3 and 1 / 3)];
How to do ah, help, thank you, how to write the format

+(-4）=-4
-(- 5 1 / 2) = 5 1 / 2
-[+ (- 3 1 / 3)] = 3 1 / 3
There is no format, just write like this, rule: negative is positive, positive and negative is negative, positive and negative is positive

To know the data x1, X2, X3 If the average of XN is 3 and the variance is 4, then the data 3x1, 3x2, 3x3 The average of 3XN is The variance is_

To know the data x1, X2, X3 If the average of XN is 3 and the variance is 4, then the data 3x1, 3x2, 3x3 The average of 3XN is__ 3*3=9____ The variance is_ 4*3^2=36______
If every data is expanded n times, the average is n times and the variance is n times square

Mingming's kitchen is 3 meters long and 2.6 meters wide. I want to re tile the kitchen until it is 1.6 meters high,
The area of doors and windows under 1.6 meters is 2 square meters, and the ceramic tile is a square with side length of 20 cm. How many ceramic tiles do you need?

398 not counting consumables

When to use Archimedes principle? When to use f = g~

Archimedes principle is applicable to all buoyancy calculations, whether floating, floating or sinking; F floating = g row
Only when gravity and buoyancy are in balance, i.e. floating and suspending, can we use: F floating = g objects, but at this time, Archimedes principle is still applicable, i.e. f floating = g objects = g rows

What is the domain of arcsinx + π / 4 ≥ 0

Answer: [- (radical 2) / 2,1]
The original formula is arcsinx ≥ - π / 4
Where the function y = SiNx is simple increasing, then the function y = arcsinx is simple increasing on [- 1,1]
(the monotonicity of function and its inverse function in corresponding interval is the same)
When x belongs to [- π, π], sin (π / 4) =: - (radical 2) / 2
So: x > = - (radical 2) / 2
The domain of y = arcsinx is [- 1,1]
So:: [- (radical 2) / 2,1]

After three squares of the same size are put together into a rectangle, the surface area is 16 square centimeters less than the original, and the volume of the rectangle is calculated

The area of one face of cube is 16 △ 4 = 4 square centimeter
4=2×2
The length of the cube is 2 cm
Cuboid Volume 2 × 2 × 2 × 3 = 24 CC

A = 0.00.025 (1997 zeros) B = 0.00.08 (2000 zeros) a △ B=

If we expand AB by 2000 times at the same time, 25000 divided by 8 is equal to 3125

The known function f (x) = 2cos2x + cos (2x + π / 3) - 1
(1) Finding the minimum positive period and monotone increasing interval of F (x)
(2) If the acute angle a satisfies f (a) = - 3 / 2, calculate the value of angle A
It's 2cos squared

1）f(x)=2cos^2x+cos(2x+π/3)-1
=cos2x+cos2xcosπ/3-sin2xsinπ/3
=cos2x+1/2cos2x-√3/2sin2x
=3/2cos2x-√3/2sin2x
=√3(cos2xcosπ/6-sin2xsinπ/6)
=√3cos(2x+π/6)
So the minimum period T = 2 π / w = 2 π / 2 = π
Because when (2x + π / 6) ∈ (2k π - π, 2K π), f (x) increases monotonically
Then x ∈ (K π - 7 π / 12, K π - π / 12)
So the monotone increasing interval of F (x) is (K π - 7 π / 12, K π - π / 12) (K ∈ z)
2）f(a)=√3cos(2a+π/6)=-3/2
Then cos (2x + π / 6) = - √ 3 / 2
That is, 2x + π / 6 = k π + 5 π / 6
x=kπ/2+π/3 (k∈Z）
Because a is an acute angle
So a = π / 3

The circumference of a square is 36 cm, and its side length is______ Cm