The function f (x) = 1 / (4 ^ x + 2) (x ∈ R), if X1 + x2 = 1, then f (x1) + F (x2) =? Moreover, if n ∈ positive integer, then f (1 / N) + F (2 / N) + +f[(n+1)/ n]+f(n/n)=?

The function f (x) = 1 / (4 ^ x + 2) (x ∈ R), if X1 + x2 = 1, then f (x1) + F (x2) =? Moreover, if n ∈ positive integer, then f (1 / N) + F (2 / N) + +f[(n+1)/ n]+f(n/n)=?

f(x1)+f(x2)=1/（4^x1 +2）+1/（4^x1 +2）=(4^x1 +4^x2 +4）/【4^(x1+x2) +2*4^x1 +2*4^x2 +4】=4^x1 +4^x2 +4）/（4 +2*4^x1 +2*4^x2 +4）=4^x1 +4^x2 +4）/2（4^x1 +4^x2 +4）/）=1/2f(1/n)+f(2/n)+…… +f[(n+1)/ ...

The function y = f (x) defined on R satisfies f (4-x) = f (x), (X-2) f '(x)

From the condition f (4-x) = f (x), it is concluded that f (2-x) = f (2 + x), so f (x) is axisymmetric with respect to x = 2
If x1 ＜ x2 and X1 + x2 = 4, x1 ＜ 2 and X2 ＞ 2 can be obtained
So from (x1-2) f '(x1) < 0, we can know that f' (x1) > 0
Similarly, f '(x2) < 0
So the function increases first and then decreases (similar to parabola with downward opening). Because it is impossible to determine which of X1 and X2 is close to the axis of symmetry, D
Ps... it seems that it's not right to choose D, but that's the result

The factorization of polynomial 4x ^ 3 - 4x ^ 2Y + XY ^ 2 is?

The original formula = x (4x & # 178; - 4xy + Y & # 178;)
=x(2x-y)²

Is the sum of the four corners of the trapezoid equal to 360 degrees

Sum of internal angles = 180 * [4-2] = 360 degrees
Sum of internal angles = 180 * [n-2]

The absolute value equation │ 2x-3 │ = 1, │ 3x-2 │ - 1 = 3

Because │ 2x-3 │ = 1
So 2x-3 = 1 or 2x-3 = - 1
The results are as follows
X = 2 or x = 1
Because │ 3x-2 │ - 1 = 3
So 3x-2 = 4 or 3x-2 = - 4
The results of solving these two equations are as follows
X = 2 or x = - 2 / 3

Define a new operation: a divided by B = 3 times a + 4 times B, then 10 divided by 11 = ()
Please! It's urgent!

10/11=x
10/11*11=x*11
10=x*11=3x+44
x=-34/3

Find the limit of e ^ X / X when x approaches 0

So it's in the form of 1 / 0, and the limit is infinite

How to calculate 9 / 7 * 11 / 5 + 9 / 5 * 11 / 1

Original formula = 9 / 5 * 11 / 7 + 9 / 5 * 11 / 1 = 9 / 5 * (11 / 7 + 11 / 1) = 9 / 5 * 88 / 7 = 792 / 35

An applied problem of factorization
The hydraulic press (cylinder) has m hollow steel columns, each of which is h m in height, d m in outer diameter and d m in inner diameter. The mass of each cubic meter of steel is g tons. The total mass of M columns w? Is calculated, where H (D-D) = - 10.8, m (D + D) = 5.6, g = 7.8 and π = 3.14

Volume of a hollow steel column = bottom area * height = ((1 / 2) π d ^ 2 - (1 / 2) π d ^ 2) * H = 1 / 2 π (D-D) (D + D)
The mass of a hollow steel column is density * volume = g * ((1 / 2) π d ^ 2 - (1 / 2) π d ^ 2) * H = 1 / 2 π (D-D) (D + D)
Mass of M hollow steel columns = g * ((1 / 2) π d ^ 2 - (1 / 2) π d ^ 2) * H = 1 / 2 π (D-D) (D + D) * m
It is known that h (D-D) = - 10.8, m (D + D) = 5.6, g = 7.8, π = 3.14
The final answer is -740.63808
However, the answer is negative, which is unreasonable. The problem is that "H (D-D) = - 10.8" the outer diameter inner diameter should be a positive number
In this way, H (D-D) should be 10.8, so the reasonable answer should be 740.63808
^-^

How to divide 63 by 1.8
This is age four,

63 divided by 9 and then divided by 0.2
63÷（9×0.2）＝63÷9÷0.2＝7÷0.2＝35