Tech Hammer

Holidays make people happy, traveling makes people happy, and falling in love makes people happy. When these three things happen at the same time, it is cubic happiness.

I got up from bed at six o'clock in the morning, and then happily took a shower. After washing, I put on my favorite youth clothes, looked left and right in the mirror, and ran into the study after feeling perfect. March said hello, of course it was a simple hello, leaving behind one sentence: "I'm going on a date, you should be good at home!"

Then he turned around and walked out of the house coolly, pacing and arriving at the women's dormitory downstairs at seven o'clock at the appointed time. To his surprise, Jiang Chenshuang was already waiting for him at the door.

Obviously, the girl also dressed up specially. The clothes were "work clothes" chosen by Yu Xingwei, which included an off-white sweater, a long camel coat, a pair of light blue jeans and a pair of simple sneakers. It looks youthful and fashionable.

Although Yu Xingwei is not here at the moment, Ning Wei still gives him a thumbs up from the bottom of his heart. To be honest, he quite admires Brother Yu. Although he usually acts very straight, when it comes to choosing clothes for girls, Quite appreciative.

What Ning Wei didn't know was that this actually had nothing to do with being discerning. Yu Xingwei just randomly picked a similar brand store based on the fee given by Ning Wei, and then told the girls selling clothes his request. All the clothes and matching are actually based on those young ladies’ reference...

This probably also confirms that professional things must be left to professionals to be worry-free and happy.

"What are you looking at?" Although the two have established a relationship, Jiang Chenshuang still can't stand Ning Wei's hot gaze.

"I think you look like my future wife!"

Ning Wei solemnly gave the standard answer in his heart, with a tone as serious and solemn as a math problem, which made the girl lower her head again. Then Ning Wei took a step forward as a matter of course, took the beauty's little hand and complained: "It's all agreed. What else is there to be ashamed of? By the way, have you completed all your study tasks?"

"Yeah!" Student Jiang responded.

"That's fine. If you have anything you don't understand about advanced mathematics and line generation, you can ask me later on the way, but you are not allowed to ask when you get to the place. You have to relax wholeheartedly when playing." Ning Wei said.

"Oh, the adjoint matrix problem of linear algebra, I read the book but I still don't understand it very well." Jiang Chenshuang said honestly.

Ning Wei nodded and replied: "Adjoint matrix? Well, when you encounter problems with adjoint matrices, you have to remember some formulas. Let me tell you, the professors in the School of Mathematics will not give you pure answers when they give questions. Adjoint matrix problems are usually combined with inverse matrices to set test points. Moreover, this kind of question has its own characteristics and has many solutions. I will teach you the most clever solution. As long as you see the adjoint matrix problem, whether it is a proof question or All calculation problems are analyzed from the formula AA^*=A^*A=|A|E."

"Some conclusions can be used directly, such as if r(A)=n, then r(A^*)=n, if r(A)=n-1, then r(A^*)=1, if r (A)\u003cn-1, then r(A^*)=0. To give you an example, let A be an n-order non-zero matrix, A^* is the adjoint matrix of A, when A^t=A^ *, prove that |A| is not equal to zero. How do you think about adding the formula just now?"

Jiang Chenshuang blinked and suddenly realized that Ning Wei seemed to have made the question that had been bothering her less difficult with just a few words. She thought about it and replied: "Oh, then we should directly substitute A^t=A^* into AA^* =A^*A=|A|E, we get AA^*=AA^t=|A|E, and then use the proof by contradiction method, let |A| equal to zero, let the row vector of A be αi, in this case αiαi ^t is equal to zero, so A is equal to zero, which contradicts |A| is equal to zero, so |A| is not equal to zero.”

After hearing the answer, Ning Wei looked at the girl next to him approvingly and said, "You still say you don't understand. I think you understand it quite well. You just found the simplest way to prove it. Then it will be more difficult for me to test you." The question is, you are ready, let’s assume matrix A =..."

In this way, Ningwei gave examples to the girls around him and then explained them, from simple to difficult, in just twenty minutes from the dormitory to the entrance of the Institute of Mathematics. Jiang Chenshuang really felt that the adjoint matrix problem that had been bothering her seemed impossible. Question, and by the way, I also consolidated the concepts of inverse matrices and irreversible matrices...

It’s a very strange experience. Really, Jiang, who is in love for the first time, actually doesn’t know if other people are similar when they fall in love. I just simply feel that if this is love, it will not delay but will promote learning. , no wonder Yanbei University has never objected to students falling in love on campus.

When the two of them arrived at the entrance of the Institute of Mathematics, a black Audi was already parked at the entrance. Ning Wei glanced at the license plate. It was the license plate his account manager had issued to him yesterday. He checked the time and then It was just 7:20, and he had made an appointment with the bank to leave at 7:30. It seemed that the driver had also arrived early. Everyone was on time today.

The driver was a young master who looked to be in his thirties, wearing white gloves. When he saw Ning Wei and Jiang Chenshuang coming to the door, he immediately got out of the car and said to Ning Wei: "Hello, Mr. Ning, I am Chen Guangming, who contacted you yesterday, I will also serve you these days, please get in the car."

"Hello, Master Chen. Thank you for your hard work these days." Ning Wei nodded, then pulled Jiang Chenshuang, who was still dazed, into the back seat of the car.

"Where did you get the car?" the girl asked in a low voice.

"I don't know about the services provided by the bank. Don't worry about it. Do you understand what I just told you?" Ning Wei explained.

"I seem to understand, but I feel like I need to do more examples to consolidate." Jiang Chenshuang answered honestly.

"Well, if you still have problems with the accompanying matrix, then you must have a little understanding of the linear correlation problem. Wait, Master Chen, how long does it take to get from school to the Forbidden City?"

"Well, if there's no traffic jam, it will take about forty minutes."

"Oh, that's enough time, thank you, Master Chen!"

After receiving the answer, Ning Wei turned his head and continued: "Let me tell you, the correlation or irrelevance of vector groups is a very abstract concept. When you see related questions, you have to pay attention to that there is a group that has a different meaning from any ancestor. , the former only requires existence, while the latter requires everything, emphasizing arbitrariness. For example, if I give a condition, there are vector groups α1, α2...αs, and there is always 0α1+0α2+...+0αs=0, then the vector group Whether α1, α2...αs are linearly related, in fact, the question is whether, in addition to the situation I just mentioned, another set of k1, k2...ks can be found, such that k1a1+... is true.

"Sounds very simple, right? Let me give you another example. Suppose A is an n-order matrix and α is an n-dimensional column vector. If A^m-1α is not equal to zero, and A^mα is equal to zero, prove that the vector group α, Aα, A^2α,… are linearly independent.”

The lecture was really about the topic. The only thing that was a little too much was that Ning Wei, who was sitting in the car and lecturing the girl next to him, was no longer content with holding her little hand, but naturally put his arms around the girl during the lecture. Waist, of course, he didn't stop talking, and even the examples came at his fingertips. Although he didn't speak fast, Jiang Chenshuang had to concentrate hard to keep up with Ning Wei's narration. Facts have proved that people can really ignore it when they are extremely focused. The surrounding situation.

So until classmate Jiang started thinking about the example given by Ning Wei, and when he probably had the result and wanted to speak, he suddenly realized that he seemed to be in Ning Wei's arms. What happened?

But before she could twist her body, Ning Wei continued: "Haven't you figured out the proof steps yet? You have to think about the problem based on the previous mathematical concepts."

Classmate Jiang replied uneasily: "I understand..."

"You have to tell me that you have figured it out. If you don't tell me, how will you know that you have figured it out?"

"Is that what you're saying?" Student Jiang twisted his body unnaturally.

"Um? Is there something wrong? This is not a confidential issue. It's the simplest line generation issue. Are you afraid that the driver will know about it? When you study, you have to be focused and undistracted, and you have to have the kind of attitude that keeps you calm even if the mountain collapses. Do you know the stable mentality? Especially when studying mathematics, you may be distracted and miss a knowledge point, resulting in the follow-up questions not being understood. You see, you are studying and thinking about problems now. If you don't concentrate enough and think about random things, you don't want to do this." Ning Wei tilted his head and said sadly.

These words seemed to make sense. Jiang Chenshuang couldn't find any reason to protest or object, so she could only lean into Ning Wei's arms obediently and said softly: "Oh, just use the definition you mentioned before and multiply them together. First... …”

"Well, yes, this idea is completely correct, but it is not the simplest way. In fact, there is a little trick. When you get K2A^m-1α=0, you can directly substitute K1 equal to zero into the formula, and then you can The conclusion is drawn directly. Next, I will give you more difficult debut questions..."

Ning Wei was very happy to talk, and it was not just the nephrite in his arms that made him proud and excited, but he felt that Jiang was so smart, and all the knowledge points could be explained in just one lecture. Of course, he also played a part in this. Ning Wei did not follow the content in the textbook step by step, but based on his understanding, he broke down all the important and difficult points, and then analyzed the context clearly...

The car was parked in a parking lot very close to the Forbidden City.

For Ning Wei, he really doesn't understand that ordinary cars can't drive here, especially on a special day like National Day. Naturally, he didn't know that in order to do this, the bank had issued a temporary special pass for the car specially prepared for his VVIP customer.

After dragging Mr. Jiang out of the car so generously, he was recognized by a middle-aged woman who had also just gotten off the car and was probably visiting the Forbidden City.

"Hey, are you Ning Wei? Wow, Ning Wei is the god of learning. My son admires you the most. Can he take a photo with you? Is this your girlfriend? Let's take a photo together?"

How can I put it this way, it was the first time for Ningwei to meet a fan's mother asking for a photo when traveling. However, Ning Wei has experience with this kind of thing. When he was at Jiang University, he had encountered many situations where he asked for a group photo. When he was in a good mood, he pulled Jiang and asked the other driver to help him. Zhang Ying officially started today’s journey after saying a friendly goodbye.

"By the way, I discussed it with Senior Brother Lu yesterday. Senior Brother Lu suggested that my sister simply come to the high school attached to our school to study. What do you think?" In the crisp autumn weather, Ning Wei held his girlfriend's little hand and felt refreshed. asked.

"Of course it would be best if you could come. You can also take care of your sister nearby. But didn't you say before that you were an only child? Is it your cousin or cousin?" Jiang asked.

"My father and my mother are both the youngest in the family. How can I have cousins? I have two cousins. I'm talking about Jiang Chenlu. By the way, isn't your sister my sister? Since you think it's fine, that's fine. Then I will ask her directly tonight what she thinks. If she agrees, I will find someone to make arrangements later. This way you can take care of her nearby." Ning Wei replied matter-of-factly.

"Ah? You're talking about Chenlu? No need, right? And you have to trouble others. It's very troublesome to apply for a loan. Let's not trouble others, okay?" Jiang Chenshuang was stunned and quickly shook Ning Wei's arm. said.

"Trouble others? Let me tell you, what our field director is afraid of now is that I won't trouble him, really! If you don't believe me, I'll call our field director right now and ask him, why don't I ask him to help me while I'm studying for my Ph.D. Busy, does he feel uneasy in his heart? If I beg him for such a trivial matter, he would have to thank you and Chen Lu for giving him such a simple opportunity to help! This is not what I said, it was Lu Senior Brother’s analysis, if you don’t dare to ask Director Tian, ​​you can ask Senior Brother Lu after your holiday! This is not me bragging, Director Tian’s exact words, he asked me to inform him before posting on Weibo, as long as I agree, Let him do whatever he wants!"

Ning Wei said confidently.

Jiang Chenshuang looked at Ning Wei blankly. She could understand the math problem just now, but asking the tutor for help and having the tutor express her gratitude was really beyond her understanding.

"I tell you this and you won't understand. The story is very complicated. But one thing you should understand is that the teacher's teaching level has a direct impact on students' academic performance. This is why teachers have always been valued by parents. The reason is the simplest. Do you think the line generation difficulties I just explained to you are easy to understand?" Ning Wei turned around and asked.

Jiang Chenshuang nodded subconsciously. This was indeed no exaggeration. She really felt that Ning Wei's explanation was so broken that she understood what she had memorized by rote almost instantly.

"Look, do you think the teachers in our capital city are stronger or the teachers in a small county or small town there? It is not safe for a non-provincial key high school to be the first in the grade, Chen Shuang! The college entrance examination is a lifetime matter , forget it if you can’t think of it, now that we have the ability to solve the problem, can we let Chenlu lose at the starting line?”

The logic line was expressed extremely strictly, especially using his own teaching method as an argument, which made Jiang Chenshuang unable to express any objection at all.

"Okay, that's it. I'll discuss it with my sister later. Let's go. I heard that the Forbidden City is huge. We need to take a good look..."