![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
There are three red, black and white balls in box a, and two yellow, black and white balls in box B. take one ball from each box. Calculate the probability that the two balls are of different colors
A problem of probability in mathematics compulsory 3
What's the probability of ABCDEFG taking any two letters from it, at least one of which is a or B? (1) take it out and put it back. (2) take it out and don't put it back
There is also a small problem, when AB and Ba belong to the same situation, and when they are different
thank you!
(1) 2 / 7 + 5 / 7 * 2 / 7 = 24 / 49
(2) It is 2 / 7 + 5 / 7 * 2 / 6 = 11 / 21
When there is a calculation order, AB and Ba are different
For the above questions, there is no difference
Why is an event with a probability of 0 not necessarily impossible
This is mainly the case for continuous random variables. Take an example to show that if the random variable x obeys the uniform distribution on [0,1], then the probability of X taking each value is 0, but it is not impossible,
I didn't bring a book with me. I only remember the title number. It's page 98, page 3, page 101, page 5 and page 113, page 1
This is a picture
2 times 1200X = 2000 (22-x) 2400x = 44000-2000x4400x = 44000x = 1098 page 3 page 101 page 5 page 1 page 1 page 1 page 2 page 1 page 2 page 1 page 2 page 1 page 2 page 1 page 2 page 1 page 2 page 1 page 2 page 1 page 2 page 2 page 2 page 2 page 1
Given the displacement, acceleration and initial velocity, how to calculate the time,
Don't put x = v0t + 1 / 2at in that direction
From vt & # 178; - vo & # 178; = 2As;
Vt=√（2as+Vo²） …… （1）
From vt = VO + at, we can get the following results
t=（Vt-Vo）/a …… （2）
Substituting (1) into (2) yields:
t=[√（2as+Vo²）-Vo]/a
Mathematics, linear equation with one variable, profit problem
Xiaoming's family bought a 5-year treasury bond with interest rate of 2.97%. After maturity, they got a total of principal and interest and 5742.5 yuan. How many yuan of treasury bonds did Xiaoming buy that year? Fast!
5×2.97%=0.1485
5742.5 ÷ (1 + 0.1485) = 5000 yuan
Given acceleration, find displacement and time
Common conditions:
It takes 9 seconds for a small ball to speed up in a straight line at a constant speed from a standstill to a speed of 100 km / h
What is the distance between the starting point and the current position when a small ball accelerates from a stationary uniform speed to 100 km / h?
2. When the small ball accelerates from a static uniform speed in a straight line, when it is 100 meters away from the starting point, what is the speed at this moment? How many seconds does it take?
100km / h = 100000 / 3600 = 27.8m/s (1) v = ATA = V / T = 27.8 / 9 = 3.1m/s & # - 178; X = at & # - 178; / 2 = 3.1 * 81 / 2 = 125.6m; the distance between the starting point and the current position is 125.6m (2) V & # - 178; = 2axv = √ 2aX = √ 2 * 3.1 * 100 = 25m / SX = at & # - 178; / 2T = √ 2x / a = √ 200 / 3.1 = 8s
Unit 1: knowledge summary of rational multiplication and division
The first chapter is rational number 1.1 positive and negative numbers. The number with negative sign before the number other than 0 is called negative number. It has the opposite meaning with negative number, that is, the number other than 0 is called positive number (sometimes add "+" before the positive number if necessary)
All formulas of acceleration and displacement
A = △ V / △ t a = f / M (F is the external force on the object) a = V2 / R2 (centripetal acceleration) s = VT (uniform linear motion) s = VT + 1 / 2at2 (uniform acceleration linear motion with initial velocity V) s = 1 / 2T (V + V1) (uniform acceleration linear motion with initial velocity V and final velocity V1)
Who can help me write a summary of rational numbers in the first volume of the people's education press,
The general content is OK, the answer will have heavy thanks!
Rational number English: rational number pronunciation: y ǒ u l ǐ sh ù integers and fractions are collectively called rational numbers. Any rational number can be written in the form of fraction M / N (m, n are integers, and N ≠ 0). Therefore, rational number is also called fraction. Fraction is called λ ο γ ο in Greek, which originally means "proportional number
RELATED INFORMATIONS
- 1. 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
- 2. It is easy to give an example that the event with probability 0 is not an impossible event, and the event with probability 1 is not an inevitable event It's better to be more detailed
- 3. Probability of independent events A. B is two random events, P (a) = 0.5, P (b) = 0.3, if a and B are independent Then p (AUB) =?
- 4. Why is a zero probability event not necessarily impossible
- 5. It is known that the quadratic trinomial x2-2 (M + 1) x + 9 is a complete square, then M=______ ．
- 6. Expression of power function f (x) passing through point m (3, √ 3)
- 7. Given the function g (x) = 1 + 2x, f [g (x)] = 1 + x2 / X2, find the expression of F (x)
- 8. Can a in all trigonometric functions of the form y = asin (Wx + F) + B be represented by (ymax Ymin) / 2, or is it necessary for y to be symmetric about the X axis?
- 9. It is known that the period of the function f (x) = asinwx + bcoswx + 1 defined on R is π, F (π / 4) = root 3 + 1, and the maximum value of F (x) is 3 1. Write the f (x) expression 2. Write down the center of the pile, the axis of symmetry, and the axis 3. Explain how the image of F (x) is transformed from the image of function y = 2sin2x
- 10. How to find the period according to the harmonic motion image The vertical axis is amplitude and the horizontal axis is time
- 11. There are 10 students in a group, including 3 girls. Two representatives are elected. The probability of at least one girl being elected is () A. 715B. 815C. 35D. 25
- 12. Take any two balls from the pocket with two red balls and two white balls. In the following groups, the two events are mutually exclusive and not antagonistic______ (please write down all the serial numbers you think meet the requirements) ① at least one white ball; all white balls; ② at least one white ball; at most one white ball; ③ exactly one white ball; exactly two white balls; ④ at least one white ball; all red balls
- 13. There is a probability problem of the occurrence of mutually exclusive events in mathematics A cube with color on each side is sawed into N3 cubes (n is greater than or equal to 3) of the same size, and the probability of any one of these cubes with color on exactly two sides is zero The correct answer is 1 - (n-2) 3 / N3, and the main explanation is (n-2) 3 Sorry, I copied the wrong topic, at least one side of the probability of color
- 14. There are two coats in Xiao Wang's wardrobe, one is red, the other is yellow, and there are three pairs of trousers, which are white, blue and yellow. If you take out a coat and a pair of trousers at will, the probability is () A. 56B. 16C. 13D. 15
- 15. In medical biological experiments, Drosophila melanogaster is often used as the test object. In a cage with 6 Drosophila melanogaster, two flies are accidentally mixed into the cage (at this time, there are 8 flies in the cage: 6 Drosophila melanogaster and 2 flies), so we have to open a small hole in the cage, let the flies fly out one by one, until both flies fly out, and then close the hole. (I) just one Drosophila melanogaster is left in the cage (II) the probability of at least five flies remaining in the cage
- 16. In the 2013 National University Games, a University selected 4 students from 6 students to participate in shot put, height adjustment, long jump and sprint respectively, then the probability of student a to participate in sprint or long jump is () A. 13B. 12C. 23D. 34
- 17. The probability of light burden, high efficiency and simple things in Mathematics (1)
- 18. In an opaque pocket, there are 12 yellow balls and several red balls. These balls have no other difference except color. After many touching tests, Xiao Li found that if the frequency value of randomly picking out a red ball is stable at 25%, the number of red balls in the bag may be 25%______ One
- 19. Suppose that the probability of occurrence of event a in three repeated independent tests is 1 / 3, X is the number of occurrence of event a in three tests, and Y is the number of occurrence of event a in the first two tests Let the probability of occurrence of event a in three repeated independent tests be 1 / 3, X denotes the number of occurrence of event a in three tests, and Y denotes the number of occurrence of event a in the first two tests. It is difficult to find the joint distribution law of (x, y)
- 20. In Bernoulli test, the probability of success of each test is p In Bernoulli test, the probability of success of each test is p, and the average number of tests is calculated until both success and failure occur