1. If we know (x = 2 / x) to the power of two = 5, then (x + 2 / x) to the power of two= 2. Calculation problem The second power of (x-1) - 4 / (x + 1) / the second power of X-9 / x + X 3、2a2-18／a(a+3)-2(a+3)÷(a-3)·a(a-3)+2(3-a)／a2-6a+9 4. Usually, when buying the same watermelon with the same quality in other aspects, people hope that the larger the proportion of watermelon ladles in the whole watermelon, the better. We regard watermelon as a sphere, and the density of watermelon ladles as uniform. The thickness of watermelon rind is a. the known volume formula of the sphere is v = 4 / 3 π R3 (where R is the radius of the sphere) (1) What is the volume ratio of watermelon ladle to the whole watermelon? (2) Let the radius of big watermelon be r, and the radius of small watermelon be r (r > R). Do you think it's cost-effective to buy big watermelon or small watermelon? Explain your reason through calculation 1. For filling in the blanks, 2,3 for calculation, 4 for application

1. If we know (x = 2 / x) to the power of two = 5, then (x + 2 / x) to the power of two= 2. Calculation problem The second power of (x-1) - 4 / (x + 1) / the second power of X-9 / x + X 3、2a2-18／a(a+3)-2(a+3)÷(a-3)·a(a-3)+2(3-a)／a2-6a+9 4. Usually, when buying the same watermelon with the same quality in other aspects, people hope that the larger the proportion of watermelon ladles in the whole watermelon, the better. We regard watermelon as a sphere, and the density of watermelon ladles as uniform. The thickness of watermelon rind is a. the known volume formula of the sphere is v = 4 / 3 π R3 (where R is the radius of the sphere) (1) What is the volume ratio of watermelon ladle to the whole watermelon? (2) Let the radius of big watermelon be r, and the radius of small watermelon be r (r > R). Do you think it's cost-effective to buy big watermelon or small watermelon? Explain your reason through calculation 1. For filling in the blanks, 2,3 for calculation, 4 for application

1) What's the volume of the whole watermelon
V = 4 / 3 え R ^ 3 (where R is the radius of watermelon)
The volume of watermelon ladle is v = 4 / 3 え (R-D) ^ 3
(2) What is the volume ratio of watermelon ladle to the whole watermelon
4/3え(R-d)^3 :4/3えR^3
=(R-d)^3 :R^3
=(1-d/R)^3
(3) It can be seen from the ratio of upper volume,
The bigger the watermelon is, the smaller the D / R is and the larger the ratio is
In other words, the bigger the watermelon, the more ladybugs, the more cost-effective

The number of unknowns is greater than the number of equations, why?

When the number of unknowns is greater than the number of equations, it is "Diophantine equation". Diophantine equation generally has infinite solutions, of course, there are non-zero solutions

The range of function f (x) = √ - X & # 178; + 2x + 2 is

-X & # 178; + 2x + 2 should be in the root
-X & # 178; + 2x + 2 symmetry axis is x = 1, the maximum value is taken when x = 1, and the maximum value is - 1 + 2 + 2 = 3,
To make the radical meaningful, we need - X & # 178; + 2x + 2 > = 0, so - X & # 178; + 2x + 2 ∈ [0,3]
The range of F (x) is [0, √ 3]

How much is the absolute value of 15 out of 17 minus 15 out of 16 minus (15 out of 16 plus 2 out of 17)

The absolute value of 15 out of 17 minus 15 out of 16 minus (15 out of 16 plus 2 out of 17)
=15/16-15/17-15/16-2/17
=-1

If 3Y equals x plus 2Z, then the square of x plus the square of 9y plus the square of 4Z minus 6xy minus 12yz plus 4XZ

x^2+9y^2+4z^2-6xy-12yt-4xz
=x^2+(x+2z)^2+4z^2-2x(x+2z)-4z(x+2z)+4xz
=x^2+x^2+4xz+4z^2+4z^2-2x^2-4xz-4xz-8z^2+4xz
=0

(√ 3 / 3) negative & # 178; × (- 3) 0 power + (2 + √ 3) - 1 power + | 1 - √ 3|
Can this problem be simplified completely? If the problem is not clear, please ask me~

Original formula = 1 / (1 / 3) × 1 + (2 - √ 3) + √ 3-1
=3+2-√3+√3-1
=4

Let E1 and E2 be two non collinear vectors, and find the value of λ when a = - 2E1 + λ E2 and B = E1-1 / 2e2 are collinear

If the vector a = - 2E1 + λ E2 and B = E1-1 / 2e2 are collinear
Then a = γ B
∴-2e1+λe2=γe1-1/2γe2
∴-2=γ
λ=-1/2γ
∴λ=1

How to solve 3 (1 x / 10 + 16) + x = 100?

3x/10+48+x=100
13x/10=52
x=40

3.5x = 1.55-1.5x to solve the equation

3.5x=1.55-1.5x
3.5x+1.5x=1.55
5x=1.55
x=0.31

(1) LG (3x-10) find the value range of X. (2) log (x + 1) (X-2). (x + 1) in the lower right corner. (3) log (x + 1) (x-1) ^ 2, (x + 1) in the lower right corner

(1) 3x-10 is greater than 0, so x is greater than 10 / 3
2, (x + 1) is greater than 0 and not equal to one, X-2 is greater than 0, so x is greater than 2
3, (x + 1) is greater than 0 and not equal to one, X-1 is not equal to 0, so x is greater than - 1 and X is not equal to 0 and 1