The probability of taking any two numbers a and B in the interval [0,1] so that the equation x ^ 2 + 2aX + B ^ 2 = 0 has two unequal real roots

The probability of taking any two numbers a and B in the interval [0,1] so that the equation x ^ 2 + 2aX + B ^ 2 = 0 has two unequal real roots

Unequal roots of real numbers
⊿=4a²-4b²>0
∴a>b
Let the interval [0,1] have n numbers,
The permutation number of any two of N numbers is:
There are only two kinds in C (n, 2) * a (2,2)
Situation: before > after, or after > before
So the probability of a > b is 1 / 2
The title condition is equivalent to a > B
In the plane rectangular coordinate system, make the image (a is the abscissa, B is the ordinate), the area that is a > b, make the line B = a, then the lower part of the line (excluding the line itself) is the result, so p (the square has two unequal real roots) = 1 / 2
Let a belong to [0,2], then what is the probability that the equation x + 2aX + 1 = 0 of X has a real root on R?
x^2+2ax+1=0
(x+a)^2=a^2-1
When a ^ 2-1 ≥ 0, there is a real root, that is, a ≤ - 1 or ≥ 1
In the interval [0,2] (0,1), there is no real number root and [1,2] has real number root,
The probability of having real roots is 50%
Zero point five
If a is a root of the equation x & # 178; + X-1 = 0, calculate 1 / {1 + 1 / [1 + 1 / (1 + a)]}
Because a is a root of the equation x & # 178; + X-1 = 0, then a & # 178; + A-1 = 0, then a & # 178; + A + 1 / 4 = 5 / 4, i.e. (a + 1 / 2) &# 178; = 5 / 4, the solution is a = (- 1 ± √ 5) / 2, from a & # 178; + A-1 = 0, we can get the relation a & # 178; + a = 1, i.e. a (a + 1) = 1, obviously a is not equal to 0, so we can get both sides of the equation at the same time
If one root of the equation a (x-1) &# 178; + k = 0 (a ≠ 0) about X is 5, then the other root is 5
a（4-1）²+k=0
k=-16a
be
（x-1）²-16=0
（x-1）²=16
x=1±4
x=5,
x=-3
On the root of the equation ∵ (x) ≠ 0, ∵,
∴a（5-1）²+k=0
∴a=-k／﹙16a﹚
∴（x-1）²=16.∴x-1=±4
｜ x = 5 or x = - 3
The other root is - 3
It takes 4 matchsticks to make the first figure, 10 matchsticks to make the second figure, and several matchsticks to make the nth figure
The first figure has a square, and the second figure has three squares
6n-2
4n+3
Light, heat, electricity, sound~
Light can make plants grow, and it can also make plants grow~
The chemical energy in food can make our body move, and also make our body move~
Light can make plants grow. It can also make us see objects that glow or are reflected
Heat can boil water, and we can get warm by heating
Electric energy can make the lights on, but also make the machine running, TV broadcast, mobile phone calls
The chemical energy in food can make our body move and keep normal temperature and metabolism
Sound energy can make paper vibrate and we can hear sound
Light can make plants grow. It can also make us see objects that are luminous or reflected. Heat can boil water, and we can get warm by heating. Electric energy can make the lights on, but also make the machine running, TV broadcast, mobile phone calls. The chemical energy in food can make our body move and keep our body at normal temperature and metabolism. Sound energy can make paper vibrate and we can hear sound. ... unfold
Light can make plants grow. It can also make us see objects that are luminous or reflected. Heat can boil water, and we can get warm by heating. Electric energy can make the lights on, but also make the machine running, TV broadcast, mobile phone calls. The chemical energy in food can make our body move and keep our body at normal temperature and metabolism. Sound energy can make paper vibrate and we can hear sound. Put it away
Light can make plants grow and water evaporate
Heat can boil water and make air flow
Electricity can light up the lights and turn the fans
The chemical energy in food can make our body move and our brain think
Sound energy can make paper vibrate and vocal cords vibrate
Light can make plants grow. It can also make us see objects that are luminous or reflected. Heat can boil water, and we can get warm by heating. Electric energy can make the lights on, but also make the machine running, TV broadcast, mobile phone calls. The chemical energy in food can make our body move and keep our body at normal temperature and metabolism. Sound energy can make paper vibrate and we can hear sound. ... unfold
Light can make plants grow. It can also make us see objects that are luminous or reflected. Heat can boil water, and we can get warm by heating. Electric energy can make the lights on, but also make the machine running, TV broadcast, mobile phone calls. The chemical energy in food can make our body move and keep our body at normal temperature and metabolism. Sound energy can make paper vibrate and we can hear sound. Put it away
The voltage is 380V, the maximum power consumption is 160kW, how much current is equal to? What kind of air switch is used!
It's hard to say. If it's all pure resistance load, 160kW is 160A. It's better to choose 200A air switch, but factory power has inductive and capacitive load. For example, when the motor starts at full load, the starting current is 3-4 times of the rated current. It's hard to say exactly how much current you want
How to add, subtract, multiply and divide a negative number?
It's better to explain separately and add examples!
Add negative numbers:
The absolute value of two numbers is added or the opposite number is added when the sign changes
Such as - 1 + (- 2) = - (1 + 2) = - 3
Minus
The absolute value of the subtracted minus the absolute value of the subtracted
Such as - 2 - (- 3) = 3-2 = 1
Multiplication of negative numbers
If there are odd negative signs in each number, the result is negative; if there are even negative signs in each number, the result is positive
For example - 1 * (- 3) * (- 2) = - 1 * 3 * 2 = - 6, - 2 * (- 4) * (- 2) * (- 1) = 2 * 4 * 2 * 1 = 16
Division of negative numbers is the same as above
-4/(-2)=4/2=2,-4/2=-2
In addition and subtraction, you can think of a minus sign as a minus sign
Then negative is positive and positive is positive
Example: (- 2) - (- 4) = 0-2 + 4 = 4-2 = 2
（-2）-4=0-2-4=0-（2+4）=-6
（-2）+（-6）=（0-2）+（0-6）=-（2+6）=-8
（-2）+6=6-2=4
Multiplication and division
（-2）×（-4）= 8
Use nine matchsticks to make a figure with five equilateral triangles ()
Use six matches to make an equilateral triangle with two matches on each side. Put three matches in it and divide the triangle into four equilateral triangles which become one match
Reference figure:
Take the middle points of three sides of a large equilateral triangle and connect them
Put nine matches on it, just four small equilateral triangles and one big one
First place an equilateral triangle with two matches on each side, and then use the remaining three matches to lay out the median line
There should be four small equilateral triangles and one large equilateral triangle
What are sound energy, light energy, electric energy, heat energy, magnetic energy, mechanical energy and chemical energy?
Urgent!
energy