An event with probability equal to one is not necessarily an inevitable event, and an event with probability equal to zero is not necessarily an impossible event

The probability of 1 is not necessarily an inevitable event. Considering the continuous random variable x, event B means that its value is any finite point in the sample space, and the probability is 0. Event a means that its value is the whole sample space, and the probability is 1, but a does not necessarily occur, and B does not necessarily occur
For example:
Let X be a continuous random variable and obey the uniform distribution from 0 to 1, that is, x ~ U (0,1), and its probability density function is
f(x)=1,0

Calculation formulas of time and displacement (at least 3 for each)
What is the formula for each of the above five? There must be at least three formulas for each

Velocity formula: VT = V0 + at ①
Displacement formula: S = v0t + AT2 ②
Velocity displacement relation: - = 2As ③
Average speed formula: = ④
= (v0 + vt) ⑤
= ⑥
The formula of displacement difference: △ s = AT2 ⑦
Formula explanation: (1) except for Formula 4, other formulas are only applicable to uniform speed change linear motion. (2) formula 6 refers to that in uniform speed change linear motion, the value of average speed in a certain period of time is exactly equal to the speed in the middle of this period of time, thus establishing a relationship between average speed and speed
6. For the uniformly accelerated linear motion with zero initial velocity, the following laws are established:
(1) At the end of 1t second, 2T second, 3T second The ratio of the velocity at the end of NT second is: 1: 2: 3 :n.
(2) . 1t seconds, 2T seconds, 3T seconds The ratio of displacement in NT seconds is: 12: 22: 32 :n2.
(3) In 1t second, 2T second, 3T second The displacement ratio in the nth second is: 1: 3: 5 :(2 n-1).
(4) In 1t second, 2T second, 3T second The ratio of the average speed in the nth second is: 1: 3: 5 :(2 n-1).

Calculation of power
|-The square of the absolute value of 2 / 3 | * 2 minus two-thirds or
The square of the absolute value of minus two-thirds

The square of the absolute value of minus two-thirds

If the acceleration of an object moving in a straight line at constant speed is a, the displacement in time t is x, and the final velocity is V, then the expression of the motion law of the object is

X = VT + 1 / 2A (the square of T) (vector formula)

A problem of power calculation
(- 0.25) to the power of 2003 and X4 to the power of 2003

(- 0.25) to the power of 2003 × 4 to the power of 2003
=(0.25 × 4)
=The power of (- 1)
=-1
This is the formula

If the object is moving in a straight line with uniform velocity, the acceleration is a and the final velocity is V, then the expression of the displacement X of the object in time t should be x = 0___ ．

Using reverse thinking, if the object moves in a straight line with constant speed and initial velocity V, and the acceleration direction is opposite, then the displacement is x = vt-12at2

An applied problem of power
Every 30 minutes a certain cell divides from one to two. After 5 minutes, how many cells does this cell divide from one to two?

Split: 5x60 / 30 = 10 times
5-hour split: 2 ^ 10 = 1024

1. If the acceleration of a moving object is a, the displacement in time t is s, and the final velocity is V, then the relationship among a, t, s and V is ()
A.S=vt+1/2at^2 B.S=-vt+1/2at^2
C.S=vt-1/2at^2 D.S=-vt-1/2at^2
2. The relationship between the displacement and time of the object moving in a straight line with uniform speed change is s = t + 1 / 2T ^ 2______ Its velocity is 3 M / s

The first question is C.S = V flat * t = [(V beginning + V end) / 2] * t = [(V beginning + V beginning + at) / 2] * t = V beginning + 1 / 2 (at ^ 2)
=[(V end + V end at) / 2] * t = V end T-1 / 2 (at ^ 2)
These are the two most commonly used formulas. Learn to deduce them and remember them
The second question, according to s = t + 1 / 2T ^ 2 compared with S = V initial T + 1 / 2 (at ^ 2), we can get V initial = 1 a = 1, according to V end = V initial + at = 1 + T = 3, we can get t = 2 seconds

An applied problem of product's power
Stack some small cubes with side length of 2A into a large cube. When there is only one small cube, one small cube can be seen, and none can be seen; when eight small cubes form a large cube, seven small cubes can be seen, and one can not be seen; when 27 small cubes form a large cube, 19 small cubes can be seen, and eight can not be seen According to the above rules: 1. When there are 216 small cubes, find the number of invisible small cubes and the volume of these small cubes; 2. When there are (n-1) ^ 3 invisible small cubes, find the surface area of the whole large cube

Rule 1: you can see that the second time you can't see one is the number of cubes piled up last time. The third time you can't see eight is the number of cubes piled up last time

When an object moves in a straight line with uniform speed change, the velocity at a certain moment is V, and then the velocity after time t is still V, then the acceleration of the object? A.0 (I know it's wrong, you don't have to choose it) b.2v/t, the direction is the same as the velocity direction before time t, c.2v/t, the direction is the same as the velocity direction after time t, d.v/t, and the direction is the same as the velocity direction after time t

Let's assume that the object starts to move to the right at a speed of V. when t = V / A, the object's speed drops to 0, and then moves to the left. After t, the object's speed is still V, but the direction is opposite to the original direction. Let's suppose V = V, VT = v'v '= V + at, that is - v = V + at, then deduce a = - 2V / T, and choose C

An event with probability equal to one is not necessarily an inevitable event, and an event with probability equal to zero is not necessarily an impossible event