How many square meters is 5 mu?

How many square meters is 5 mu?

1 mu is equal to 666.66 square meters
One hectare is equal to 10000 square meters
One hectare is equal to 100 square meters
5 mu is equal to 666.66 * 5

X ^ 2 + X-1 = 0, try to find the value of x ^ 3 + 2x ^ 2 + 1999

X^2+X-1=0 X^2+X=1
X^3+2X^2+1999
=X(X^2+X+X)+1999
=X(1+X)+1999
=X^2+X+1999
=1+1999
=2000

English word Solitaire starts with 100 apples

apple end dad death hit them math hospital late elephant table engineer rest toronto orange easy year round drive element tomato obey yeild desk kitchen never ruler remember rice estimate elder rush hear root teeth hot test tonight teen nut tell light too organic climb bread dark knock key yellow wealth hollow wait time elementary young great tower run never rude eleven no origin neck kiss slight tail lost terrible ear ruin number rope evaluate east touch host tired down near rainbow welcome eleborate else english hard dry yard destiny yes swear row weat tall last travel large eight tolerant
It's all written by myself~

In the problem of arithmetic sequence, let {an} be the arithmetic sequence, and the sum of the first n terms is SN. If A6 = 2, S5 = 30, find S8 =?

A [n] arithmetic sequence
So: s [5] = 5 * a [3] = 30, a [3] = 6
a[6] - a[3] = 3d,2 - 6 = 3d,d = -4/3
a[4] = 6 - 4/3 = 14/3
a[5] = 6 - 2 * 4/3 = 10/3
So s [8] = 4 * (a [4] + a [5]) = 4 * 8 = 32

Z = (e ^ 3Y) + (x ^ 2) xsiny, find DZ

When Z is a partial derivative of X, 2x * siny; when Z is a partial derivative of Y, 3 (e ^ 3Y) + x ^ 2 * cosy
So DZ = 2x * siny DX + 3 (e ^ 3Y) + x ^ 2 * cosy dy

A kind of rectangular car is used to transport coal. The length is 3 meters, the width is 2.5 meters, the height of coal loading is 0.4 meters, and the weight of coal per cubic meter is 1.4 tons. How many tons of coal are transported by five same cars?

3 × 2.5 × 0.4 = 3 (cubic meter); 1.4 × 3 × 5 = 21 (ton); answer: five same cars carry 21 tons of coal

How many pairs of complementary angles are there when two lines intersect at one point? Three lines? Four lines? Five lines? N lines? Tell us the exact formula

Two lines intersect at a point, there are two pairs of complementary angles
If the three lines intersect, the three angles complement each other, not the adjacent complementary angle

Given the function f (x) (x ∈ R, X ＞ 0), for any X in the domain of definition, y always has f (XY) = f (x) + F (y), and if x ＞ 1, f (x) ＞ o is constant;
It is proved that the function f (x) increases monotonically in (0, + ∞), and the number of roots of the equation f (x) = 0 is explained. If x ∈ [1, + ∞), the inequality f (x ∧ 2 + 2x + A / x) > 0 holds, and the value range of real number a is obtained

【1】 Let x = y = 1, then f (XY) = f (x) + F (y)
=>f(1)=f(1)+f(1)=2f(1)
=>f(1)=0
【2】 Let x2 > X1 > 0, then x2 / X1 > 1 = > F (x2 / x1) > o
And f (x2) = f (x1 * x2 / x1) = f (x1) + F (x2 / x1) > F (x1)
So the function f (x) increases monotonically in (0, + ∞)
Since the function f (x) increases monotonically in (0, + ∞) and f (1) = 0, then the image of function f (x) has and only has one intersection point with X axis, so the root of equation f (x) = 0 has and only has one intersection point on (0, + ∞)
【3】 It is known from [1] that 0 = f (1)
Then the inequality can be reduced to: F (x ＾ 2 + 2x + A / x) > 0 = f (1)
From [2], it can be concluded that x ∧ 2 + 2x + A / x > 1 holds for any x ∈ [1, + ∞)
That is: a > - x ^ 3-2x ^ 2 + X holds for any x ∈ [1, + ∞)
Let g (x) = - x ^ 3-2x ^ 2 + X, X ∈ [1, + ∞)
Then G '(x) = - 3x ^ 2-4x + 1
Let g '(x) = 0 = > x = [- 2 + SQR (7)] / 3 or x = [- 2-sqr (7)] / 3
∵[-2-sqr(7)]/3

The chemical properties are the same because the elements are the same? The arrangement is different because the physical properties are different? Why?
Please explain why,
Also, please solve the following problem! By the way, please explain the reason!
The physical properties of diamond and graphite are very different. Graphite is very soft, while diamond is the hardest material in nature. Graphite conducts electricity while diamond does not
A. Different structure B. different composition
C. Different uses D. different chemical properties

Choose a
Graphite and diamond are made up of carbon atoms, but different materials are formed due to different arrangement
Just like 26 English letters, different arrangements make different sentences
You should also know that the same stick, tied into a triangle is more stable than tied into a quadrilateral

How to understand the relationship between density and speed of sound and speed of light
Generally speaking, the lower the density of the medium, the higher the speed of light and the lower the speed of sound?

Remember, light doesn't need medium, and there is no resistance in vacuum, so the fastest transmission is sound. The smaller the density is, the larger the gap between materials is, the sound will pass through the air, and then spread among media. Light is like an airplane, it doesn't need a road, sound is like a car, it needs a road, and the better the road is, the faster it is