Tech Hammer

Xu Mo looked at Ning Wei proudly.

Yes, she was testing Ningwei.

It's not that Ning Wei did anything wrong, but that Xu Ruixuan is dishonest!

In fact, there is another version of the whole incident, but the two girls didn't tell it just to save Xu Ruixuan's face.

The first time we met, there were actually only three people.

Xu Mo took his best friend to attend self-study with Xu Ruixuan in the master plan, and soon discovered that this was a parallel import.

Xu Ruixuan could only admit that he actually discussed some of the problems with other students. .

Everyone made an appointment to meet the classmate who was good at math the next day.

After Xu Ruixuan returned to the dormitory, he thought carefully for a long time and felt that he still couldn't drag Ning Wei to meet Xu Mo.

If anyone in the dormitory threatens him in terms of appearance, it is only Ning Wei.

Tall, thin, handsome, with good grades...

Before he could confirm his relationship with Xu Mo, Xu Ruixuan felt that he could never let Ning Wei take action directly.

Although everyone in the dormitory has a good relationship, when it comes to future happiness, who hasn't been a little selfish?

So he called Liu Cong.

Who makes Liu Cong, nicknamed Fat Wolf, the fattest in the room? And I have a lot of acne on my face.

No matter what, Liu Cong's grades are better than his. Maybe it just got passed by?

Unfortunately, they failed again...

That's why this meeting happened.

Now it seems that Ning Wei's performance may actually be parallel imports.

After all, the question is so long, so you don’t need to read it for several minutes, right?

Little did she know that Ning Wei was extremely shocked at this moment.

If Ning Wei was not sure if there was any change in his body when he was in the dormitory, now he was sure that there was probably something wrong with his brain.

There is a saying that there is often only a thin line between genius and madman.

Ning Wei felt that he was going crazy.

…

"Do you have an idea?"

Xu Mo's question awakened Ning Wei from his own world.

First he raised his head and glanced at Xu Ruixuan, who was winking at him, and then nodded to the girl opposite.

"It's solved."

"ah?"

Xu Mo was stunned for a moment, obviously he didn't expect Ning Wei to say this. How did he explain it? Calculate silently in your mind?

"First prove a. Here we have to divide it into two steps. First prove that it is a Markov process, and then prove that it is a homogeneous Markov process."

“Because a machine tool that is working at time t, the probability of stopping at time t+△t is μ△t+O(△t); a machine tool that is not working at time t, the probability of starting to work at time t+△t is λ△t+O(△t); these results have nothing to do with the previous t and are only related to △t. The question has already stated that the machine tool works independently. From this, we know that this is a Markov process."

"The next step is the second step. It can be deduced from the conditions: Pij (△t) = P{X (t+△t) = j | X (t) = i}"

"It can be obtained from this: (N-i) λ△t+O (△t), j=i+1, that is, N-i units are broken and one is good again;"

"iμ△t+O(△t), j=i-1, that is, one of the good i units is broken;"

"1-(N-i)λ△t-iμ△t+O(△t), i=j, that is, one good one is bad, and one bad one is good;"

"O(△t), |i-j|\u003e1, that is, it is impossible to have two good and bad machines at the same time."

"It can be seen that the transition probability from t to t+△t is only related to △t and has nothing to do with t, so this Markov chain process is homogeneous."

"Then the second question is to find a stationary distribution. From the above conditions we can know..."

Ning Wei entered the problem-solving state and began to write and draw on the paper.

In fact, Ning Wei is not very good at giving lectures, but he has the most detailed problem-solving process in his mind, so he only needs to write down what is in his mind step by step.

As for whether the beauty next to her could understand, Ning Wei actually didn't care too much.

"Based on the above inference, we can conclude that P{at most three units are not working}=P{7≤X(t)≤10}=P7+P8+P9+P10=0.599."

"That is, when N=10, λ=60, μ=30, the probability that at most three units will not work in the steady state is 0.599."

…

Xu Mo took the manuscript paper that Ning Wei had used to answer the question with a blank look on his face, and then handed it to his best friend next to him.

Ning Wei was so focused on solving the problem that he didn't notice that Yang Xiaohui glanced at him from time to time when he started to solve the problem.

Yang Xiaohui took the answer sheet, opened the book she was opening, and flipped to the back. After carefully comparing it for several minutes, she said, "They are all correct, and the problem-solving process is more detailed than the reference answers in the book."

"Haha, I just said that the capable person is in our dormitory. Hey, it's not that I don't want to bring Ning Wei out. This guy is very well-behaved. He has to go to self-study with his girlfriend every day. It's hard to get him out today. Thanks to his girlfriend for giving him a holiday!"

Xu Ruixuan winked at Ning Wei.

Ning Wei finally figured out why he had a girlfriend today.

He couldn't help but laugh, and then fell silent.

Well, it seems that Xu Ruixuan really likes Xu Mo.

What he didn't know was that Luo Xiang actually wanted to speak up, but when he was solving the problem, Xu Ruixuan handed Luo Xiang a note promising meals for a week, and Luo Xiang rebelled.

Fortunately, Ning Wei has no plans to fall in love at this time.

If possible, he would even be willing to remain single for ten years in exchange for being able to figure out what happened to him today!

Anyway, I have been single for twenty-two years, and I will be single for another ten years.

He doesn't have the money or time to have a dull relationship recently.

Of course, I would rather not let go of the benefits I deserve.

"Well, Mr. Xuan, does your promise to treat me and my girlfriend to a day of wine and barbecue still count?" Ning Wei looked at the roommate opposite and asked.

"Well, it counts, it must count."

"But she said she has to lose weight recently and can't eat barbecue, so why not treat me to meals for a week?"

"Of course it's no problem!"

Just when Ning Wei was about to say something, the phone buzzed.

Ning Wei picked up the phone, smiled sheepishly at the girl next to him, then picked up the phone and went to the corridor.

"His girlfriend's?" Xu Mo asked Xu Ruixuan.

"Maybe?"

"You girls in the academy are so strict with your boyfriends!"

"Haha, just so so!"

Yang Xiaohui on the side turned her head curiously again and glanced at Ning Wei who was leaving.

These guys seem a little strange.

…

The call was from the conductor.

"Hey, Ningwei, where are you now?"

"Study in the general drawing."

"Oh, if you have time, come to my office now."

"Okay, I'll be there in about ten minutes."

"Okay, don't worry, I'll be waiting for you."

…

Returning to the study table in the two dormitories, Ningwei said apologetically: "Sorry, I have something to do and have to leave first. You can study by yourself first. See you next time."

"Are you really looking for a girlfriend?" Xu Mo asked.

"Haha..." Ning Wei laughed twice without explaining.

"Oh, it just so happens that I have something to do, so we have to go back to the dormitory and let's get together." Luo Xiang said, who could no longer sit still.

"Okay, if you have anything to do, go ahead. Remember to withdraw your seat within an hour, otherwise you will be blacklisted by the general manager." Xu Ruixuan said with a very knowledgeable look.