"Teacher, I found something wrong with the probability formula!"
"oh? Tell me your reasons. "
"There are 50 students in our class. According to the calculation, the probability of being asked is 2%, but today you almost let this course.
I answered all the questions. "
2. Possibility
I visited the weather station and saw many latest weather forecasting instruments. After the visit, I asked the stationmaster, "You said there were hundreds."
How is the 75th probability calculated when it rains? "
Without much thought, the stationmaster replied, "That is to say, there are four people here, and three of them think it will rain."
3. Death toll
Jenison, an English poet, wrote a poem, several lines of which read: "Every minute, a person is dying, and everyone.
Every minute, a person is born ... "After reading it, a mathematician wrote to question it. The letter said, "Dear Sir, stop reading. "
This is a quick job, but a few lines are illogical and it is difficult to agree. According to your algorithm, the number of casualties per minute is balanced and accurate.
The number of people on the ball is eternal. But you know, in fact, the population on the earth is growing. properly speaking
There are 1.6749 people born every minute, which is quite different from the number you provided in the poem. To be realistic,
If you don't object, I suggest you use a score of 7/6, that is, change the poem to: "One person dies every minute,
Every minute, 1. 6 people are born ... "
4. Empirical equation
The physics professor walked across the campus and met the math professor. The physics professor is doing an experiment and he has summed up an empirical formula.
Cheng seems to agree with this experimental data. He asked the math professor to look at the equation. They met a week later, the math professor said
This equation doesn't hold water. But at that time, the physics professor had predicted further experimental results with his equation, and the effect was quite good.
Good, so he asked the math professor to review the equation again. Another week later, they met again. The math professor told me
Professor v. physics said that this equation does hold, "but it only applies to the simple case of positive real numbers."
5, nailing
Engineers, physicists and mathematicians received a task at the same time: nailing the wall. Engineers built
Universal nailing machine is a machine that can nail any possible nail into any possible wall. physicist
A series of tests were made on the strength of hammers, nails and walls, and then a revolutionary technology-ultra-low temperature was developed.
Ultrasonic nailing technology. Mathematicians extend the problem to N-dimensional space, and think that a 1 dimensional nail with kink penetrates a.
The problem of N- 1 dimensional super wall. Many basic theorems have been proved. Of course, abstinence of this topic gives a simple answer.
The existence of is far from obvious.
6. Maximum area
A farmer invited engineers, physicists and mathematicians to enclose the largest area with the least fences. engineering
The teacher drew a circle and declared that it was the best design. Physicists pull the fence into a long straight line, assuming that
The fence is infinitely long, so I think it is big enough to enclose half the world. The mathematician gave them a big laugh. He seldom uses fences.
Barbara surrounded herself and said, "I'm outside now."
7. Mathematicians' answers
Physicists and engineers got lost in a hot air balloon in the Grand Canyon. They shouted for help: "Hello!
Where are we? "About 15 minutes later, they heard a response echoing in the valley:" Hey! You are in a hot air balloon.
Yes! The physicist said, "That guy must be a mathematician." The engineer wants to know, "Why?" physicist
Tao: "Because it took him a long time to give a completely correct answer, and this answer is useless."
8. The solution exists.
Engineers, chemists and mathematicians live in three adjacent rooms of an old inn. The engineer's coffee started that night.
When the machine caught fire, he woke up smelling the smoke, unplugged the coffee machine, threw it out of the window, and then went to sleep. soon
The chemist also smelled smoke when he woke up. He found that cigarette butts lit the trash can. He said to himself, "How to put out the fire?
We should lower the fuel temperature below the ignition point and isolate the combustion products from oxygen. Watering can do both. "So.
He dragged the trash can into the bathroom, turned on the tap, put out the fire and went back to sleep. Mathematicians saw all this outside the window.
So, after a while, he didn't worry at all when he found his ashes burning the sheets. Say, "hey, the solution is.
Yes! "Then go to sleep.
9. Negative numbers
Mathematicians, biologists and physicists sat in street cafes and watched people walk into a house across the street.
Get out. They first saw two people go in, and after a long time, they saw three people come out. Physicist: "Do you measure?"
Accurate enough. Biologist: "They reproduce." Mathematician: "If one more person goes in now, then the house."
It will be empty. "
10, fire protection
One day, the mathematician felt that he had had enough of mathematics and ran to the fire brigade to announce that he wanted to be a fireman. fire fighting
The captain said, "You look good, but I have to give you a test first." After the fire chief brought the mathematician to the fire brigade,
There is a warehouse, a fire hydrant and a hose in the courtyard alley. The fire chief asked, "suppose the warehouse is on fire, you
What shall we do? The mathematician replied, "I connected the fire hydrant to the water pipe, turned on the water pipe and put out the fire." firemaster
Said, "Exactly! Last question: suppose you walk into an alley and the warehouse is not on fire, what would you do? " mathematics
The economist pondered for a long time and finally replied, "I will set fire to the warehouse." The fire chief shouted, "What?
That's terrible! Why did you set fire to the warehouse? The mathematician replied, "In this way, I will simplify the problem into a problem I have."
A problem that has been solved. "
1 1, statistician
Mathematics consists of 50% formula, 50% proof and 50% imagination. Topologists can't tell coffee cups from bagels.
. The head of the statistician will say, "It feels good on average."
12, the height of the flagpole
A team of engineers are measuring the height of the flagpole. They only have a tape measure, which is difficult to fix on the flagpole because of the leather.
Rulers always fall. A mathematician passed by and pulled out the flagpole, so it was easy to measure the data. After he left, an engineer
The teacher said to the other, "Mathematicians always do this." We asked for height, but he gave us length! " "
13, difference
Constant function and exponential function ex were walking down the street, and they saw the differential operator far away. The constant function was so scared that it quickly hid and said, "Yes!"
Differentiate, I have nothing! The exponential function said unhurriedly, "It can't do anything to me, I am."
ex！ "Exponential function meets differential operator. Exponential function introduces itself: "Hello, I'm ex." The differential operator said.
: "hello, I'm d/dy!"
14, proof of prime number
Prove that all odd numbers greater than 2 are prime numbers, and different professionals have given different proofs:
Mathematician: 3 is a prime number, 5 is a prime number and 7 is a prime number. According to mathematical induction, all odd numbers greater than 2 are prime numbers.
Physicist: 3 is prime, 5 is prime, 7 is prime, 9 is experimental error, 1 1 is prime, ...
Engineer: 3 is prime, 5 is prime, 7 is prime, 9 is prime, 1 1 is prime, ...
Computer programmer: 3 is prime, 5 is prime, 7 is prime, 7 is prime, 7 is prime, …
Statistician: Let's try a few random numbers, 17 is a prime number, 23 is a prime number, 1 1 is a prime number, …
What are 15 and π?
Mathematician: π is the ratio of circumference to diameter. Engineer: π is about 22/7. Computer Programmer: Under double precision
π is 3. 14 159653589. Nutritionist: You die-hard math brains, the "pie" is delicious and healthy.
Kangde dessert
16, black sheep
Physicists, astronomers and mathematicians were walking on the Scottish Plateau when they happened to see a black sheep. "ah!"
Astronomers said, "It turns out that Scottish sheep are black." "Come on, you can't just say that based on an observation.
The physicist said, "You can only say that this kind of black sheep was found in Scotland." "No," said the mathematician.
"From this observation, you can only say: At this moment, this sheep, from our observation point of view, has one side.
It is black. "
17, no derivative everywhere.
A foreign scholar (engaged in mathematics research) came to visit our school and stayed in the foreign guest house. He's leaving.
I asked him what his impression of our school was, and he said, "The hostel in your school is so bad that it will never happen again."
Dare to live! "I quickly asked the reason. The professor said: "the mouth of the eating bowl can't be guided everywhere, so it's not for people to eat." "
Yes! "
I listened and smiled. The professor's metaphor is really vivid!
Although it is a joke, it can deepen the understanding of the concepts of continuity and derivability:)
The x power of constant function and exponential function e walked down the street and saw the differential operator from a distance. The constant function hides in fear and says, "If I differentiate by it, I have nothing!" " "
Exponential function said unhurriedly, "It can't do anything to me, I am the x power of E!" " "
Exponential function meets differential operator.
Exponential function introduces itself: "Hello, I am the x power of E."
The differential operator said, "Hello, I'm' d/dy!'" " "