Given a = {x | x = - T & # 178;, t ∈ r}, B = {y | y = x & # 178; + 3, X ∈ r}, and u = R, then A∩B=——；A∪B=——；Cu（A∪B）=——

Given a = {x | x = - T & # 178;, t ∈ r}, B = {y | y = x & # 178; + 3, X ∈ r}, and u = R, then A∩B=——；A∪B=——；Cu（A∪B）=——

Empty sets from negative infinity to 0 and from 3 to positive infinity (0,3)
What is the golden section law in economics?
The saving rate that maximizes consumption is called the golden section rate. But in the graph, why is it the intersection of a straight line with the same slope as the straight line y = NK and the curve f (k)? Why is the f (k) - SF (k) value of this intersection the largest?
When the values of a and B are what, the polynomial A's square + B's Square - 2A + 4B + 18 has the minimum value, and the minimum value is obtained
Square of a + square of B - 2A + 4B + 18
=（a-1）^2+（b+2）^2+13
So when a = 1, B = - 2, the minimum value of the original formula is 13
Square of a + square of B - 2A + 4B + 18
=（a-1）^2+（b+2）^2+13
Given the set M = {1,2,3, m}, n = {4,7, n ^ 4, n ^ 2, n ^ 2 + 3N}, m, n ∈ R, the mapping f: X → y = 3x + 1 is a function from m to N, then M =? N =?
1 - > 4,2 - > 7,3 - > 10, M - > 3M + 1, so one of n ^ 4, n ^ 2, n ^ 2 + 3N must be 10, and 4,7, n ^ 4, n ^ 2, n ^ 2 + 3N are not equal. If n ^ 4 = 10,4,7, n ^ 4, n ^ 2, n ^ 2 + 3N are not equal, 3 has two possibilities If n ^ 2 = 10,4,7, n ^ 4, n ^ 2, n ^ 2 + 3N are not equal, 3 has two possibilities Forget it for yourself
Golden section law 1.618 or 0.618
As the title
In the process of division, the division is made at about 0.618 of the total length, which is called golden section. This division point is called golden section
A line segment is divided into two parts, so that the ratio of one part to the whole length is equal to the ratio of the other part to this part. The ratio is an irrational number, which is expressed as √ 5-1 / 2 by fraction, and the approximate value of the first three digits is 0.618. Because the shape designed according to this ratio is very beautiful, it is called golden section, also known as the ratio of middle and foreign parts. This is a very interesting number, We use 0.618 to express it approximately. Through simple calculation, we can find that: 1 / 0.618 = 1.618 (1-18) / 0.618 = 0.618
The function of this value is not only reflected in art fields such as painting, sculpture, music and architecture, but also plays an important role in management and engineering design. Before and after the Renaissance, the golden section was introduced into Europe through the Arabs, and was welcomed by the Europeans. They called it "golden section", a European mathematician in the 17th century, It is even called "the most valuable algorithm among all kinds of algorithms". In India, this algorithm is called "three rate method" or "three number method", which is now commonly referred to as the proportional method
In fact, the golden section is also recorded in China. Although it is not as early as ancient Greece, it was independently created by Chinese ancient mathematicians and later introduced into India. After textual research, the proportion algorithm in Europe originated in China and was introduced into Europe from Arabia through India, rather than directly from ancient Greece
Because it has aesthetic value in plastic arts, in the design of the length and width of Arts and crafts and daily necessities, the ratio can arouse people's aesthetic feeling, and it is also widely used in real life. The ratio of some line segments in buildings adopts the golden section scientifically. The announcer on the dance stage does not stand in the center of the stage, but on one side of the stage, Even in the plant world, the golden section is also used. If you look down from the top of a twig, you can see that the leaves are arranged according to the golden section rule. In many scientific experiments, a 0.618 method is commonly used to select the scheme, that is, the optimization method, It can make us arrange fewer times of experiments reasonably and find reasonable western and suitable technological conditions. It is precisely because it has a wide and important application in architecture, literature and art, industrial and agricultural production and scientific experiments that people call it "golden section". We often hear the word "golden section", "Golden section" of course does not refer to how to divide gold. This is a metaphor, that is, the proportion of division is as precious as gold. So what's the ratio? It's 0.618. People call the dividing point of this ratio the golden section point, and 0.618 the golden number, In life, the golden section has many applications
618
0.618 is right
5 minus the root 2 and divide by 2
zero point six one eight
It's 0.618. People call the dividing point of this ratio the golden section, and 0.618 the golden number. And people think that if this ratio is met, it will be more beautiful, better looking and more harmonious. In life, the "golden section" has many applications.
zero point one six eight
zero point six one eight
zero point six one eight
It seems to have a root
zero point six one eight
The golden section ratio is 0.618!
zero point six one eight
The golden ratio is about 0.618
It's 1:0.618
618 0
The minimum value of the algebraic formula X & # 178; - 2x + 5
(x-1) ^ 2 + 4 when x = 1, there is a minimum value of 4
Let f = {(x)} (x) = {x + 1246) be known
(1) Finding f (x) analytic expression (2) finding set B
F (x) = x, that is, N / (M + x) = X
X ^ 2 + mx-n = 0 has only one solution of 3
So m = - 6, n = - 9
f(x)=-9/(x-6)
f(x+6)=-9/x
B:-9/x+x=0
X = 3 or - 3
That is: B = {3, - 3}
Golden section formula
The most basic formula of golden section line is to divide 1 into 0.618 and 0.382. They have the following characteristics: (1) any number in the sequence is composed of the sum of the first two numbers. (2) the ratio of the first number to the second number approaches a fixed constant, that is, 0.618. (3) the ratio of the second number to the first number approaches 1.618. (4) 1.618 and 0.618 are reciprocal, (5) compared with the last two numbers, the value of any number tends to be 2.618; compared with the first two numbers, the value tends to be 0.382, There are two mysterious ratios: (1) 0.191, 0.382, 0.5, 0.618, 0.809, (2) 1, 1.382, 1.5, 1.618, 2, 2.382, 2.618
When a=__ When, the algebraic formula 3A & # 178; + 5 has the minimum value, and the minimum value is___
A=0
The minimum is 5
When a = 0
That formula has a minimum of 5
A = 0, because the minimum square can only be 0
When a = 0, the algebraic expression 3A & # 178; + 5 has a minimum value, which is 5
The function f (x) = - 3x square + m (6-m) x + N, if the solution set of F (x) > 0 is (1,2), then Mn =?
process
The solution set of F (x) > 0 is (1,2)
One