Chapter 23 Be Responsible for Xu Qingzhou Xu Qingzhou laughed and separated from Song Yao at the street corner. Song Yao was stunned at first, then realized that she was being teased. At this time, Xu Qingzhou had already walked away. She could only glare at his back angrily and turned to walk towards her own community. The Song family’s community is similar to the Wutong community, both of which are old communities. On the way, Song Yao thought it through and decided to talk to her father about this matter. People like Li Dingkang were very confusing and might cause trouble for Xu Qingzhou. Although she and Xu Qingzhou did not have any close relationship, she still had to be responsible for him because it was caused by her. When she returned, Zhang Junli was cooking and said, "Your father just called and said he would be back for dinner tonight." Song Yao had just put down her schoolbag when the door opened and Song Shisong came back. "Captain Song finally decided to come back." Zhang Junli joked. Song Shisong knew that he was in the wrong and was running around outside every day, so he could only laugh it off and said, "I'm on vacation these two days, and I'll take care of all the housework."
"Dad, wash your hands and eat." Song Yao helped serve the dishes. Her mother actually understood her father's work, but she always felt that her father worked too hard and did not take his health seriously, so she wanted to say something to him every time. A family of three sat happily at the dinner table. "I have a meeting tomorrow morning. Remember to pay the electricity bill. Do you know where the electricity card is?" Zhang Junli looked at Song Shisong. "Yes, it's in the second drawer." Song Shisong was careful and saw that his daughter seemed absent-minded, so he couldn't help asking, "Xiaoyao, what are you thinking about?" "Someone bullied me." Song Yao put down his chopsticks and said. The old couple stopped what they were doing and the living room fell silent. "Tell me what happened." Zhang Junli's tone was serious. "There is a guy named Li Dingkang in our school. He was in the same class with me in junior high school. After entering high school, he kept pestering me." Song Shisong's face changed, he suppressed his anger and said seriously: "Xiaoyao, why didn't you tell me such an important thing earlier." "Dad, Mom, it's not that serious. I can handle these myself." After Song Yao finished speaking, she seemed a little distressed and said, "He just blocked the school with flowers to confess his love, and Xu Qingzhou came out to help me. I'm afraid that Li Dingkang will find someone to retaliate against him." Hearing the name Xu Qingzhou, Song Shisong's anger became complicated. His daughter had endured it for so long, and suddenly she talked about this matter because she was worried that Xu Qingzhou would be retaliated against. Zhang Junli picked up a piece of pork ribs for Song Yao, feeling a little distressed, "It's okay, Xiaoyao, leave this matter to your father. If you can't even handle a small thug, then what's the point of being a captain? Just go back to the countryside and farm." "My daughter, let your dad handle this matter." Song Shisong also said in a deep voice. "Okay, thank you Dad." Song Yao felt that this matter should be fine. Sure enough, after dinner, Song Shisong, who had just said he was on vacation, picked up the car keys and said that there was something going on at the bureau and he had to go out. At noon, after lunch, Xu Qingzhou went to the library with his notebook to continue reading. Halmos's "Naive Set Theory".
He is currently reading "A Study of Methods of Nonlinear Differential Equations" and at the same time, he is reading Gauss's work on calculus and geometry "A General Study of Surfaces". After that, he wanted to extend his knowledge a little bit and try to use nonlinear differential equations to analyze geometric structures. So he used the examples in the geometry textbook to perform operations on nonlinear calculus equations. 【Surface modeling and reconstruction. 】 First, we use nonlinear integral equations to describe the basic geometric properties of the surface. We first express the surface as a function (z = f(x, y)), where ((x, y)) is the coordinate on the surface and (z) is the corresponding height. A set of discrete data points: [ , 1, , 2] y coordinate: [0, 0, 0, 0, 0] z coordinate: [0, , , , ] Call ~ Xu Qingzhou looked up and rubbed his temple, only to notice that Song Yao had sat down opposite him at some point and was working on her homework seriously. She was wearing a waistcoat dress today, revealing her delicate collarbone, her skin was as white as snow, and her long eyelashes were trembling slightly. Song Yao seemed to realize that Xu Qingzhou had finished, so she stopped and pushed the water on her table towards Xu Qingzhou. "Thank you." Xu Qingzhou was not polite and picked up the bottle and took two big gulps. After drinking the water, my mind became much clearer. "I want to see what you wrote." Song Yao looked at the draft paper in front of Xu Qingzhou. Xu Qingzhou handed it over and said, "I just tried to use nonlinear calculus equations to describe the surface structure, and the process went smoothly." Looking at the densely packed characters on the draft paper, Song Yao couldn't help feeling depressed. She was still struggling with high school math problems while others had already started working on university-level derivations. Oh, pervert. After the second mock exam, my entire high school life seemed to be accelerated and time passed by very quickly. On campus, the atmosphere of the college entrance examination is becoming increasingly strong. Everyone is like a wound-up spring, starting to sprint for the college entrance examination with all their might. As the weather gets hotter, more students are walking on the playground in the evening. Some of them come out to relieve stress, another group feels the atmosphere of parting and simply come out for a walk and chat, and some are couples who are about to face the breakup season. Teachers have changed their teaching methods. They no longer lecture students as they did before, trying to cram all the knowledge into students' heads. Instead, they have begun to guide students' mindsets and identify and fill in the gaps. In May, the third model exam is coming. Xu Qingzhou's score increased by 10 points to 720, still ranking first in the grade. The grades of the entire senior year have improved a lot because the questions in this exam were much simpler. To put it bluntly, the purpose is to boost students' confidence in the college entrance examination. In the classroom, the fan hummed, blending with the voices of the teachers' lectures. Time just slips away in the heat and noise of summer. Zhang Yuxin approached Xu Qingzhou three times, but was rejected seriously each time. After the third mock test, the other party seemed to have lost interest and suddenly gave up, which surprised Xu Qingzhou. I thought she had finally come to terms with it. He was not idle either, and continued to read mathematics books. In fact, that was all the knowledge he had learned in undergraduate studies. The first one is high-dimensional nonlinear problems: from the oldest three-body problem, to the NS equations of fluid dynamics, to Einstein's general relativity equations, it involves a wide range of aspects, contains a lot of knowledge and is quite difficult. Second, the limit problem: the core content of calculus is the limit, and the limit definition is one of the most difficult contents to understand in this course. The limit definition is specifically divided into the definition of series and the definition of function. Because it involves a lot of function content, it is difficult to understand. The third is function problems: including primary function problems, intermediate function problems and advanced function problems, covering a relatively wide range. Mathematics is an extremely vast subject. Not to mention other advanced things, even the three points mentioned above are enough for most people to spend their entire lives studying.
However, the content he is currently exposed to is not too difficult for Xu Qingzhou. He has learned it before, but he has not been exposed to it in a more in-depth and systematic way. (End of this chapter)