Tech Hammer

After Ning Wei confirmed that he seemed to know everything in English, Luo Xiang also took his meal back to his dormitory.

Very rich.

Five dishes and one soup, not counting two chicken drumsticks.

The two people who had already eaten in advance were so greedy that they drooled.

In Luo Xiang's words, the most important thing for Ning Wei now is to turn grief and anger into food.

As the saying goes, if you eat three hundred lychees a day, you can only leave your name by eating them.

Ning Wei hesitated again and again, and finally decided not to tell anyone about his small change.

After all, he didn't want to appear different from the others.

There are three good-natured big talkers in the dormitory who have taught Ning Wei countless lessons. As long as two people know any personal secret in school, it can become a secret known to the whole class within two hours at most.

Under the envious eyes of Liu Cong and Xu Ruixuan, after having a good meal, Luo Xiang took the initiative and said: "I will accompany you to study hall today. Think about it carefully, although I was transferred to our math college, since I have accepted my fate , you still have to take the postgraduate entrance examination. You can’t be unemployed just after graduation, how embarrassing!”

Then as soon as Luo Xiang finished speaking, Xu Ruixuan said immediately: "No, leave it to me and Liu Cong to accompany Lao Ning to self-study. Lao Luo, what should you do? Why go?" Postgraduate entrance exam!"

Ning Wei was speechless.

There are two students in the dormitory who have been transferred to the Department of Mathematics and Applied Mathematics.

One is Luo Xiang and the other is Xu Ruixuan.

When they were freshmen, they were both gearing up and studying hard, vowing to study hard and fulfill their long-cherished wish to change majors before their junior year and return to their favorite school, the School of Science and Technology.

The ideal is beautiful, but the reality is often skinny.

Although Jiangcheng University is not as outrageous as other schools that require students to transfer to the top ten percent of their grade, it is still very difficult to transfer to the School of Computer Science as the most popular major.

For example, the average grade point of all courses studied in the original major should not be less than 3.5 and the math score in the college entrance examination should not be less than 85% of the total score in a single subject, so they were directly dismissed.

Xu Ruixuan was satisfied with the second item, but he felt that his average GPA in mathematics was 3.5, and he still changed his major!

As for Luo Xiang, he was stuck in the Mathematics Institute because of his math scores in the college entrance examination.

Quite ironic!

In short, after a year of jumping around in freshman year, the two chose to lie down, and then discovered that lying down was so happy, and they couldn't control it.

At any rate, Ning Wei won the second prize in the provincial competition of CMC Mathematics in his sophomore year.

As for Liu Cong, he probably just wanted to protect himself.

Luo Xiang and Xu Ruixuan were completely flat.

Apart from failing the class, I basically couldn't get any results.

To avoid failing the course, he must thank Ning Wei and Liu Cong for their friendly support in every final exam, especially for professional courses such as complex variable functions, differential geometry, and linear control systems. Luo Xiang basically relied on Ning Wei to risk his life to save him. A lucky pass.

"You? Postgraduate entrance examination?" Ning Wei rolled his eyes at Luo Xiang and Xu Ruixuan.

After three years, everyone knows the basics.

Luo Xiang's family is actually in good condition. Even if his major is relatively unpopular, it won't be a big problem to find a job after graduation. Therefore, the postgraduate entrance examination has never been a must for Luo Xiang.

As for Xu Ruixuan, all his family members were civil servants, so they just waited for him to return home and take the civil service exam after graduating from college.

"Don't look down on people! Not only do I take the postgraduate entrance examination, but I also take the cross-professional postgraduate entrance examination. By the way, Master Xuan, didn't you say that you have a cousin from far away who is a teacher at Tsinghua University? Go and ask the postgraduate students at Tsinghua University if it is good for the entrance examination!"

"Haha, Luo Xiang, it's not that I'm rejecting you. If you can ask this question, your IQ will have nothing to do with Tsinghua University in this life, really. You should continue to lie down and spend time with your child... er, with Ning. For things like the postgraduate entrance examination, Liu Cong and I are enough."

…

In the end, the three people in the dormitory took Ning Wei to study hall together.

Liu Cong and Xu Ruixuan were particularly active.

I also brought two exercise books.

Jiangcheng University is also very user-friendly in its study room arrangements.

Generally speaking, most of the teaching buildings closest to the junior dormitories of the four major departments will be open as study rooms during non-class hours.

However, when the weather is hot, whether it is the air-conditioned study room in the teaching building, the library, or the canteen open for self-study, it is more popular, and seats are often not available.

But there was a heavy rain today, the temperature was comfortable, and the breeze blowing on my face was refreshing but not hot, so I no longer had this problem.

"Where are you going to study? Teach 5?" Ning Wei, who was pulled out of the dormitory by the middle, asked depressedly.

It happened that he didn't want to go to self-study today, but he was dragged to study by two guys who probably didn't even know which way the door of the study room opened.

I don't know how to describe this feeling.

"Go to the general map, there are many beauties there!" Xu Ruixuan immediately rejected Ning Wei's proposal.

Teaching 5 is a self-study room frequently visited by science and engineering students, and the main library is a public self-study room belonging to the entire school.

There are few female students majoring in science and engineering, but there are still many beauties majoring in liberal arts and art majors at Jiangcheng University.

For example, the School of Liberal Arts and the School of Economics and Management not only have reasonable proportions, but also have a large base.

Xu Ruixuan was embarrassed by the three disdainful glances and was about to change his mind.

"Forget it, since everyone is out as a group, let's satisfy the little thoughts of the guy with the nastiest thoughts in the dormitory. The general picture is the general picture. When the child is older, it is normal for him to like to see beautiful women."

"Haha..." Xu Ruixuan looked at Luo Xiang and sneered.

"There will definitely be no seats in the general drawing's study room at this time, and we don't have a reservation. If we really want to go to the library, we might as well go to the letter drawing or engineering drawing to try our luck." Ning Wei explained helplessly.

"Don't be afraid, just follow me!" Xu Ruixuan said with a mysterious smile.

After finishing speaking, Xu Ruixuan said with an upright face: "It's boring to go to self-study directly. Let's play an interesting game. If there is a position in the general plan, how about admitting that you have a girlfriend?"

Ning Wei is a little confused. What does it mean to admit that he has a girlfriend?

Would he deny that he has a girlfriend?

He doesn't have a girlfriend at all, okay?

"What's the meaning?"

"It's just a game. If a girl asks you later if you have a girlfriend, you have to definitely say yes!"

"The probability is basically 0!"

"Let's tell you first whether you agree or not!"

"Just promise him, it's just for fun anyway!" Liu Cong helped.

Luo Xiang looked at the two of them suspiciously and said, "No, why do I feel like you have some conspiracy?"

"Okay, I have a girlfriend! Let's go to the headquarters quickly, shall we?" Ning Wei said with a headache.

He was afraid of the great masters in the dormitory.

But suddenly I remembered that everyone knew each other’s library accounts of four people. Did Xu Ruixuan really reserve a seat in advance?

…

Sure enough, when they arrived at the main library, they swiped their student cards and all four of them entered the library smoothly.

It also shows that seats have been reserved in advance.

Before Ning Wei understood what was going on, Xu Ruixuan took him to a secluded corner of the study room on the third floor.

This is a table for six people, and two girls are already sitting there, reading books.

"I would like to solemnly introduce you two ladies. This is Ning Wei, the student who has been helping you solve postgraduate entrance examination questions behind your back."

Xu Ruixuan said very formally.

Ning Wei was a little confused.

"You are just Ning Wei. Thank you these days. Thank you also to Liu Cong and Xu Ruixuan." One of the girls with long hair raised her head and said gracefully.

Luo Xiang was the first to react.

"Oh, no wonder you've been grinding through Ningwei with a few questions every day lately. So that's what's going on! Come on, you proposed to go out to study together in the dormitory today. So that's what's going on."

"Bah, Lao Luo, you are thinking too much. In fact, we only want to take Ning Wei with us, and we did not want to take you with us. You must follow us."

"Stop talking nonsense, let me introduce you first. This is Xu Mo, and this is Xu Mo's roommate and best friend Yang Xiaohui. Ning Wei, you all know each other. The loser who likes to argue is called Luo Xiang. He and the internet celebrity teacher Although they have the same name, their abilities are about 10,000 times worse." Liu Cong explained seriously.

"hehe……"

"Pooh!"

…

A few young people exchanged words with each other and soon Ningwei understood what was going on.

This started when school started last month.

Xu Mo and Yang Xiaohui decided to take the postgraduate entrance examination early and recently started reviewing mathematics. After being troubled by a math problem that kept him awake at night, Xu Mo posted a post directly on the school BBS. It probably meant that he had suffered from endocrine disorders due to the math...

This post happened to be seen by Xu Ruixuan.

Thinking that the postgraduate entrance examination for the economics and management major only requires three tests, wouldn't he, a student from a mathematics college, have it all at his fingertips?

So I took the initiative to chat privately to help others.

Of course, Ning Wei knew very well that there was a high probability that this guy was a girl when he saw the gender column and couldn't help but want to tease her.

After communicating on BBS for a while, the two actually added WeChat last week, and Xu Mo also started sending questions to Xu Ruixuan offline for answers.

What happens next will become clear.

When Xu Ruixuan discovered that even the top three postgraduate entrance examination questions were an unattainable obstacle for the two of them, he first communicated with Liu Cong. After discovering that Liu Cong was not good enough, he began to talk to Ning Wei, the best student in the dormitory. Frequent academic exchanges.

Until this afternoon, Liu Cong and Xu Ruixuan ran to meet people offline.

But there were some things that they couldn't hide anymore, and the two girls were more curious about the guy who had been silently helping them solve problems behind their backs, so this scene happened.

Xu Ruixuan and Liu Cong dragged Ning Wei down to the general study area for nothing.

Nowadays, sitting with six people is also very particular.

Yang Xiaohui sat on the far left side of the wall, near the window. Next to her was Xu Mo. Ning Wei sat next to the girl at Xu Mo's request, and Luo Xiang sat opposite Ning Wei.

Xu Ruixuan reluctantly sat opposite Xu Mo, and Liu Cong could only sit opposite Yang Xiaohui, by the window.

"I heard Liu Cong said that you are super good at mathematics and have won a national mathematics competition award?" After the four people had chosen their respective positions, Xu Mo curiously asked Ning Wei beside him.

There is a kind of awesomeness, which is called awesomeness by brothers.

The actual situation is that Ning Wei only won the provincial award, and he needed to enter the finals for the national award, and he was not notified at all.

But it seemed that Liu Cong couldn't lose face at this time, so Ning Wei could only say a vague "hmm" and then tried to turn his attention to the book.

Fortunately, Xu Mo was not his type.

He likes the small and gentle kind. Xu Mo is tall and tall, which is indeed better matched with the muscular Xu Ruixuan or Liu Cong.

The girl next to Xu Mo, who was wearing a green dress, was thin, and was obviously more introverted, was more attracted to Ning Wei.

However, she basically didn't speak. When they first met, her eyes turned to Ning Wei, and then she started to lower her head and read a book by herself.

Fortunately, Ning Wei didn't have any bad thoughts.

fall in love?

nonexistent!

No money!

…

"If you want to be so good, help me with this question." Xu Mo handed over an A4 paper with the question printed on it unceremoniously.

Ning Wei took it and looked at it.

"There are N machine tools in a workshop. Because of the need to change tools and measure, the machine tools need to work sometimes and stop sometimes. Suppose a machine tool is working at time t. The probability of stopping working at time t+△t is μ△t+O (△ t), and then assuming that a machine tool is not working at time t, the probability of starting to work at t+△t is λ△t+O (△t), and the working conditions of each machine tool are relatively independent. Use X (t) to represent t The number of machines working at all times.”

"Verify: a, {X(t), t≥0} is a homogeneous Markov chain process;"

"b. Find its stationary distribution;"

"c. Especially when N=10, λ=60, μ=30, find the probability that at most three units will not work in the steady state."

…

Ning Wei's first feeling after reading this title was that he was speechless.

How funny!

Since when does counting three require candidates to eliminate the process?

But the next moment, Ning Wei was shocked.

Because before he had time to start thinking about where to start with this problem, the complete problem-solving process automatically emerged in his mind.

Very concise, complete, and includes the answer to the last question.

The probability that at most three units are not working is 0.599.

Not only that, but there were also many related concepts in his mind that he had only a partial understanding of, such as Markov chains.

It even extended related machine learning algorithms, Markov random fields and Markov decision-making.

This feeling seems familiar...