But to say he was a scoundrel, he wasn’t quite that bad. As Xu Zhi prepared to go up reluctantly, she heard him cough lightly beside her ear. Looking at the blackboard, he casually reminded her, “You can use Lagrange’s theorem.”
However, they were studying definite integrals, and Lagrange’s theorem was a topic from two weeks ago. Judging by the writing on the multi-function blackboard, Professor Wang was supposed to be teaching the Mean Value Theorem for Integrals today. But Xu Zhi hadn’t been paying attention for the first part of the class and hadn’t fully grasped the Mean Value Theorem for Integrals. She couldn’t just go up and write out the process, so following Chen Luzhou’s hint, she thought about how to solve it using Lagrange’s theorem.
The classroom was silent, with only the sound of Xu Zhi’s chalk on the blackboard. Professor Wang was exceptionally patient, waiting for her to finish before making a rare joke, “Well, here’s another girl who can’t forget Lagrange, but he and Cauchy are a pair.”
The Lagrange Mean Value Theorem is a special case of the Cauchy theorem, and some professors jokingly refer to them as a couple. Lagrange had also been Cauchy’s teacher at one point.
Hearing this, the classroom erupted in laughter. Even Chen Luzhou couldn’t help but twitch the corner of his mouth. Professor Wang asked Xu Zhi to return to her seat, then tapped the multi-function blackboard and said seriously, “For this problem, every year I have students who come up and, without considering anything else, just start with Lagrange. When they can’t solve it, they look at me constipated, saying ‘Teacher, I can’t solve it.’ But this is good. This year, someone solved it using Lagrange. Indeed, this problem can be solved using Lagrange’s theorem.”
The professor was very serious, but his words were funny. The more serious a teacher is when saying such things, the funnier it becomes. The classroom once again burst into waves of laughter, with students laughing so hard they were bending forwards and backward. It was the first time they realized Professor Wang could be quite humorous. Professor Wang was a famous calculus professor at A University, also teaching advanced algebra for the mathematics department. But the calculus for their two classes was relatively simple, and Professor Wang’s requirements for them were also relatively low, just aiming for them to pass. So most of the time, there wasn’t much interaction in class, only requiring their attendance to be full.
But impressive teachers perhaps need to encounter impressive students to reveal their charm. Similarly, when encountering a student who could flexibly apply theorems, Professor Wang inevitably became more excited than usual. Whether it was the reflection or something else, the eyes behind his glasses were much brighter. He slowly sipped tea from his thermos, swallowed a tea leaf, and said, “Alright, back to the point. I’ll demonstrate this problem again using today’s method.”
The classroom instantly fell silent, with everyone looking straight at the blackboard, frantically taking notes. Xu Zhi saw that the guy next to her was still in the same position, leaning back in his chair. There was indeed a notebook open on his desk, but not a single word had been written in it, except for the answer he had just written for her.
To be honest, having known him for so long, Xu Zhi had never properly seen his handwriting. There were just a few Arabic numerals and letter formulas on the page. One could only say that these few numbers were written quite freely, but it was impossible to discern his handwriting. Chen Luzhou noticed her staring at his notebook and smiled, covering it with his hand. With some intuition, he asked, “Want to see the handsome guy’s writing?”
“…Where’s your shame?” Xu Zhi glanced at him sideways, deliberately saying, “You don’t need to take notes when listening to gibberish?”
Chen Luzhou glanced back at her calmly, justifying himself: “Why take notes on gibberish?”
Xu Zhi felt he was showing off too much. She looked at the blackboard expressionlessly and said, “Did you secretly study at home? You even know about Lagrange.”
Chen Luzhou also looked at the blackboard, both of them pretending to be more serious than the other, before he explained in a low voice, “No, we learned Lagrange’s theorem in high school. During the first class this morning, I just quickly flipped through the first few chapters of calculus and found it slightly simpler than I thought. But I didn’t expect Professor Wang to teach so fast. It’s only been a month since school started, and we’re already at definite integrals. It’s just a lucky guess. If it were a different problem, we’d both be at a loss.”
Indeed, Chen Luzhou had only scanned through the first few chapters in the first class. Derivative functions, up to Lagrange and Cauchy, were still simple. He had learned some basic calculus before, but it got a bit challenging towards the end, which was why he had sent that WeChat message to Xu Zhi. Indeed, if he had directly attended Professor Wang’s class today, although it wouldn’t have been completely incomprehensible, it definitely wouldn’t have been easy.
But Xu Zhi curiously asked, “You learned Lagrange in high school math? Is No. 1 High School that intense?”
Professor Wang was progressing quickly, having finished explaining the theorem and now discussing examples from the book. Chen Luzhou leaned back, one hand in his pocket, the other holding a pen to mark the examples Professor Wang was explaining in the book. Hearing her question, he chuckled, then put down his pen and casually glanced at her, saying, “No, when I was in the competition class in high school, the teacher taught it. But it was for the physics competition. Lagrange is more useful in physics competitions. Our math teacher, remember? Jiang Changwei. Several times when we asked him if we could use calculus for some problems, he told us not to learn calculus so early. It’s like—”
He paused, realizing this wasn’t quite appropriate, but Jiang Changwei had indeed told them this at the time.
Xu Zhi looked at him puzzled, only to hear Chen Luzhou cough and say uncomfortably, lowering his voice and trying to quickly and unclearly slip in those two words, “He said there’s no need to enhance male potency at twenty—”
Xu Zhi realized Chen Luzhou was still both arrogant and pure. She laughed, “Teacher Jiang has quite a way with words.”
Chen Luzhou rarely felt awkward and just hummed in agreement, coldly looking down and saying, “Anyway, that’s the idea. He’s different from other teachers. He said high school math can be solved with high school knowledge. If you insist on using calculus to solve high school math, it’s like using a sledgehammer to crack a nut. Only those lacking skill would do that. Skilled people can cook a big pot of food with just a spoon. That’s the idea. He always wanted us to use small methods to solve big problems, not use a cannon to kill a mosquito. So we only heard about it a few times during physics competitions.” After saying this, he sighed and smiled, “Next time, let’s sit separately. If we keep chatting like this, we’ll both fail this year.”
Mainly because he found that he really couldn’t concentrate. Before she arrived, he could at least understand a few examples, but now he couldn’t understand a single problem. Fortunately, Professor Wang didn’t like to call on people to answer questions.
Just then, Professor Wang asked from the podium, “Alright, after explaining so much, which option should we choose for this problem?”
A classmate: “B.”
Xu Zhi: “A.”
Professor Wang said emphatically, “Correct, this young lady reacts very quickly. It’s A, just as we discussed, the Newton-Leibniz formula—”
Chen Luzhou: “…”
Still so good at multitasking, huh?
For the second half of the class, Xu Zhi concentrated on taking notes. Chen Luzhou looked at the blackboard, his Adam’s apple rolling slightly, and suddenly asked, “Do you have time this weekend?”
At this moment, Professor Wang was writing on the blackboard with his back to them. Behind him, a sea of heads were buried, furiously taking notes. Xu Zhi was also lowering her head to write, occasionally lifting her eyelids to look at the blackboard, not even glancing in his direction, and said, “What for?”
“I want to tutor you in math,” he said shamelessly.
Xu Zhi, with half her head resting on the desk, also chuckled and glanced at him, “Chen Luzhou, have you seen a TV drama? You’re speaking just like it now.”
“Which one? Tell me,” he said lazily.
“‘Minglou, kneel, Big Sister is asking you a favor.’ It’s ‘The Disguiser,’ right? I suggest you watch it. You just had that vibe.”
He laughed, “Alright, you just want to see me embarrassed every day not understanding the class.”
Xu Zhi said with a straight face, “What if I call Zhu Yangqi right now? Do you think he’d take a taxi from Fengtai overnight to come and watch if he knew about your situation?”
Chen Luzhou leaned back in his chair without speaking. Xu Zhi looked at him for a while as he remained silent, then glanced over and heard him say thoughtfully, “…You’ve reminded me. Why don’t we invite him for a meal this weekend? Don’t tell him I’m here yet.”
“I have a department gathering this weekend,” Xu Zhi unexpectedly threw out.
Chen Luzhou made an “oh” sound, and lowered his head to flip to the front of the book to the derivative functions, preparing to start reading from the beginning. He directly stopped listening and casually responded, “Okay.”
There was a ten-minute break in the middle of the class. Professor Wang went out to smoke a cigarette, and a few male students also went out to smoke. Xu Zhi and Chen Luzhou were sitting in the front row. When Zhao Tianqi was leaving, he came around from the back row and called out to Chen Luzhou, asking if he wanted to go out for a smoke.
Xu Zhi instinctively looked at Chen Luzhou, who had somehow stuffed candy in his mouth and was slowly chewing it. He pretended and said, “Can’t smoke, my lungs aren’t great.”
Didn’t feel like your lungs were bad when we were kissing. Chen Luzhou was quite good at handling relationships. If he had simply said “I don’t smoke,” some people might think he was being pretentious. His skill lay in being able to get along with anyone, having a way of interacting with people, and another set for dealing with ghosts.
Zhao Tianqi nodded but didn’t leave immediately. He looked at Xu Zhi hesitantly, then took the initiative to chat with her, saying, “What happened to Liu Yisi just now?”
Actually, despite his ambiguous relationship with Liu Yisi for so long, Xu Zhi had never formally met him or spoken to him. She had only heard his name. If he hadn’t taken the initiative to speak to Xu Zhi, she probably wouldn’t have known he was her roommate’s ambiguous partner even if she had run into him on the street.
So when Zhao Tianqi spoke, Xu Zhi didn’t react at first, thinking he was talking to Chen Luzhou. It took her a while to realize he was talking to her, but she didn’t have a good impression of him and coldly replied, “Nothing.”
Zhao Tianqi’s eyes scanned between the two of them, seemingly wanting to ask something, but since neither of them was familiar with him, they obviously wouldn’t tell him. He left quite tactfully. As soon as he left, Xu Zhi said to Chen Luzhou, “Guess what he wanted to ask just now.”
Chen Luzhou said, “No need to guess, he’ll ask me when we get back to the dorm. I bet your two roommates won’t be idle either.”
Chen Luzhou had underestimated others’ curiosity. They didn’t even have to wait until they got back to the dorm. While Xu Zhi was still eating in the cafeteria, she was already interrogated by Xu Gongzhu and Liu Yisi.
Xu Zhi took a big bite of her lion’s head meatball and said nonchalantly, “Wasn’t I late? His seat happened to be by the door, so I just sat there.”
“You should have seen it, several girls in the back row kept staring at you,” Xu Gongzhu said, poking open a bottle of milk. “But Chen Luzhou is also from your S Province, right? Did you two know each other before?”
Xu Zhi was surprised: “You guys found out his name so quickly? Yeah, we knew each other. He used to be the campus heartthrob at our No. 1 High School.”
“He’s probably the campus heartthrob now too. I heard some girls are already calling him ‘Lu Grass’ (a play on his name meaning ‘grass’). Don’t know who came up with that nickname,” Xu Gongzhu said. “No wonder you two chatted for half the class and seemed quite happy.”
Liu Yisi: “Xu Zhi, do you think Chen Luzhou might like you?”
Xu Zhi sighed, “Probably a little bit.”
Xu Gongzhu also sighed silently: “Xu Zhi, if I had half your confidence, I wouldn’t be single.”