"Dad, I'm back. ”

The crisp and pleasant voice sounded outside Zeng Danqing's study, it was the voice of her daughter Zeng Xin.

"Dad, are you free, I have a question for you. ”

Zeng Danqing's family, everyone has an independent study, usually without permission, Zeng Danqing generally prohibits others from entering his study, and his daughter is no exception.

"Come in, Xinxin. ”

Zeng Xin pushed open the door and entered, the beautiful figure of the girl and the antique atmosphere of the study complemented each other, and she held an exercise book in her hand.

Zeng Xin has a pair of big eyes, sparkling, handsome face with big eyes, which is eye-catching wherever he goes.

Although she is wearing a school uniform, she can't hide her well-proportioned and slender figure, she walks lightly, but her demeanor seems to reveal a maturity and confidence that is not commensurate with the girl's age, and she has a leisurely bearing.

"Dad, this high school math is too difficult, my classmates and I are on the way home, discussing a topic, why are the answers of the two people completely different?"

"Xinxin, are you in high school?"

"Dad, you don't care about me too much, people are in high school, you don't even know. ”

Zeng Xin pulled Zeng Danqing's arm and scolded him.

"Xinxin, my baby daughter, you are so smart, do you still need to worry about your father about reading a book?"

From childhood to adulthood, that is, before her daughter was ten years old, Zeng Danqing often accompanied Zeng Xin to play, and took her to develop good reading habits, and then Zeng Danqing didn't care much about Zeng Xin's studies, and Zeng Xin's academic performance has always been one of the best in school, and after graduating from junior high school, she was successfully admitted to the best high school in Mudi Qingshan City.

Zeng Xin's chores in life, dealing with school teachers, are usually taken care of by her mother. However, except for the usual going to and from school, Zeng Xin has almost no extra things for her mother to take care of.

"Okay, Dad, I don't blame you if you seem to have something to do, but this high school math is really difficult, it's only been a week since school started, and I often have to do it for a long time. You promised me that I would have to think and solve the problems in junior high school, and when I got to high school, I would ask you again when I had problems, no, it really stumped me. ”

"After so many years, Xinxin, aren't you worried that your father has forgotten the content of high school?"

"Dad, you bragged to me not long ago, saying that when you were in high school, your math, physics and chemistry grades were top, and you still clearly remember a lot of ingenious problem-solving methods, and said that when you were studying for a doctorate, you also went to review high school textbooks with your supervisor. ”

After a pause, Zeng Xin seemed to understand something, and became anxious, his little face was a little crimson.

"Dad, you want to be like when I was in junior high school, throw off the burden and ignore my studies, and also say that you can solve your own problems by yourself, saying that it is to cultivate my independent learning ability. He also said that his grandparents were illiterate, and that did not prevent you from being trained as a doctoral student. Not this time, you are not allowed to make excuses, you can't just do your own thing, regardless of my studies, my classmates are still waiting outside for the right answer. ”

This is not to boast, Zeng Danqing was in high school, mathematics, physics and chemistry grades were indeed the top in the school, he liked to be in a free atmosphere, free memory and imagination, and the study of mathematics, physics and chemistry gave him this kind of freedom. His grades in other subjects were very average, mainly because he was not interested in other subjects at that time and didn't want to spend more time on rote memorization.

Although he was not admitted to the best university in the college entrance examination, he was still admitted to Kitano University, a university ranked among the top 20 in the country. He went on to complete his Ph.D. at the same university, with a bachelor's degree in basic mathematics and physics, and a master's and a doctorate in computer science.

"Okay, I'll show you. ”

"That's pretty much it, hee-hee. Dad, you see, it's this question 16, my answer is this, my classmate's answer is this, well, the process is written here. I felt that mine was right and hers was wrong, but I pushed it twice, and I didn't know why I was right and why she was wrong. ”

Zeng Danqing looked at the question and hesitated, after all, he hadn't been exposed to high school math problems for twenty-six years.

Soon, he entered the role of doing problems in the past, he quickly wrote a few strokes in the exercise book, and then said to his daughter:

"Xinxin, your answer is right, but your process is wrong, this question is a quadratic function question type, and it is also a classification discussion question, you need to do a classification discussion on this uncertain parameter a, you neglect to classify the solution on different value ranges, and only consider the discriminant formula less than or equal to zero. This type of question belongs to the type of question that is answered separately and then combined. It's just a coincidence that your process, although incorrect, deduces an answer that is consistent with the correct answer. Your basic judgment has a certain amount of truth, but when you learn mathematics, you can't rely on the correct answer under this kind of coincidence, and you can only solve the problem in a standardized and rigorous way. The right steps will lead to the right results, otherwise, you may not be so lucky next time. ”

Zeng Xin seemed to understand, but it was not so clear, after all, this content had just been learned, and the school teacher didn't talk about it.

"Then my classmate, why is she wrong? Dad, what is the correct step, you didn't write it. ”

"Your classmate considered the classification discussion, but misinterpreted this quadratic function question type as a question type that must have a solution to a quadratic equation, because when I was studying in junior high school, I did too many problems to solve quadratic equations and formed a habit. Her discriminant formula is reversed, and it is written as greater than or equal to zero. ”

"Dad, go out and talk to my classmate, she argued with me all the way. You also wrote the process to us to see, and I still don't fully understand. On the way out of school, I bragged to her about how good you are at mathematics, physics and chemistry, so that she can see and understand. ”

Zeng Xin took the exercise book, couldn't help but say, and pulled her father out of the study.

On the leather sofa in the living room, a young girl sits and plays with her backpack.

Seeing Zeng Danqing and them coming out, the girl stood up.

The girl was about fifteen or sixteen years old, tall and tall, and every part of her body was extremely well-proportioned, and her thighs were especially slender and graceful.

She was wearing a school uniform, a short-sleeved shirt on the upper body, and pants on the lower body.

The fair skin is like a lychee that has been peeled off, crystal clear.

Her face resembles a melon seed face, but it has a natural roundness.

Her eyebrows, like two shallow crescents, seem to be natural, parallel to the horizon and parallel to the horizon. All the beauty in heaven and earth seems to be concentrated under this round of crescent moon. It's a beauty like no other, a beauty of nature, a beauty of nature.

Her beauty is even more reflected in the fact that all the beauty is just right, no more, no less.

Her eyes, clear and calm, without a trace of impurities, seemed to have a tenderness, a gaze, scattered in all directions, but seemed to be projected only on the only one, everyone who saw her eyes. made everyone who saw her eyes feel that she was looking at him.