Gong Rihui's brows twitched fiercely, feeling that this guy was pretending, but he couldn't say anything, after all, this reason was normal.
"This problem-solving method can broaden your thinking and will be of great help to you in the future. But at this stage, I still recommend using conventional methods to solve problems. You should retain this kind of problem-solving thinking, but you cannot do it because of
Walking alone in a different way and forgetting the original method.”
"After all, sometimes the more basic something is, the more truth it contains."
"Also, what have you learned about mathematics in college?"
Gong Rihui looked at Xu Chuan and asked, this boy's talent is really one of the best he has ever seen in his teaching career. It would be a waste not to learn mathematics.
Maybe this competition is an opportunity. If you teach him well, you might be able to turn him into mathematics. After all, he is only seventeen years old, so it is not too late to start learning now.
"I've almost finished reading advanced algebra, differential geometry, partial differential equations, and ordinary differential equations."
Xu Chuan selected some college mathematics answers for studying physics.
Although he must have learned more mathematics than these, those deeper things and mathematics that are not used in competition with objects are obviously not suitable to be mentioned now.
"Oh? Then I'll give you another question."
It is clear that the limit of the second question must be solved with Lupida, and this is the easiest solution. There are simple ones that are not used, but complex ones must be used. Is this a brain problem?
But since he asked, Xu Chuan looked at the question again, thought for a while, and replied: "Calculus is not good. It should be possible to solve the limit of definite integrals, but you have to convert the question into definite integrals first, and then solve it.
"
"Next, twist the original inequality into M(x+y+z+s)≥9|xyzs|(x+y+z=0)"
Next to him, the round-faced Lu Tianrui came over curiously. Although he had not finished the two questions on the blackboard, it did not affect his enjoyment at all.
How to find the smallest real number M?
Should I change the formula first to make both sides equal? Or should I set the condition first? It seems like neither of them works?
"Brother Chuan, can you do it?"
This familiar method seems to have just been learned from Xu Chuan's problem solving, but this kid's foundation in integral calculus is not that solid. It is not impossible to find the limit with definite integrals, but it has a range of applications, and this thing can't be solved.
When calculating the points, it went directly to the wrong point.
I stared at the manuscript paper in my hand for a long time, and suddenly, the little round face came over again.
"Use calculus to solve the slope of the curve. Brother Chuan, you are awesome! Why didn't I think of this?"
"Show me, show me, Brother Chuan."
"One is about finding inequalities and one is about matrices. It looks very interesting."
When he saw the calculus formula, he was once again stunned.
A quarter of an hour later, a piece of manuscript paper with two questions returned to Xu Chuan's desk.
Suddenly, a somewhat familiar disintegration method and answer came into his eyes. When he saw the name, it was Lu Tianrui.
Why are you so perverted?
Suddenly, Lu Tianrui seemed to have thought of something, and reached out to take the draft paper on Xu Chuan's desk that he had used to solve the problem.
Xu Chuan took the manuscript paper over with some curiosity, but it was snatched away before he could even read the question. Would this force a mathematical genius to become autistic?
Although the questions were selected from various competition textbooks, they have also been changed by him. He knows the answers and solutions to these questions very clearly. He can tell right from wrong at a glance.
"Then let a-b=x, b-c=y, c-a=z, a+b+c=s, then"
two,.
The first question caught his eye, but before he even read the second question, Lu Tianrui was a little dumbfounded. He couldn't find a place to start with an inequality at the first time.
"Gan! Even if I'm not as good as you in physics, math is my strength!"
He casually took out a piece of draft paper and pen from Xu Chuan's desk, and sat down on the desk next to him.
After saying that, Gong Rihui returned to the podium and continued to drink tea, read newspapers and fish.
On the podium, Gong Rihui, who had just read the solution to the problem and was familiar with the answer, angrily smashed a half-broken piece of chalk directly onto Xiao Yuan's head.
Xu Chuan stared at the manuscript paper and replied. As he spoke, he began to answer questions on the manuscript paper.
1. Find the smallest real number M such that the inequality is true for all real numbers a, b, c
|ab(a-b)+bc(b-c)+ca(c-a)|≤M(a+b+c)
The former is widely used in physics, and the latter is related to quantum theory and system dynamics. These are all knowledge points that he still has in his memory. He doesn't have to stay up late tonight to read through books to revive these two pieces of knowledge.
.
Lu Tianrui murmured to himself, staring at the answer on the draft paper and lost in thought. There is no doubt that Xu Chuan's problem-solving method opened up a new mind for him.
"Is it so difficult?"
"First transform this inequality into ab(a-b)+bc(b-c)+ca(c-a)=-(a-b)(b-c)(c-a)(a+b+c)."
Hearing this, Xu Chuan looked at the little fat man strangely. He understood a little bit how Teacher Gong felt before.
Gong Rihui was a little surprised. He didn't expect that this kid had seen so much college mathematics, which was comparable to students who could enter the national team.
Lu Tianrui suddenly ejected like a corpse and asked urgently.
Looking at the transformation inequalities that Xu Chuan had listed on the manuscript paper for a while, Lu Tianrui suddenly wailed, attracting the attention of others in the classroom.
After studying for a while, he still couldn't figure out how to solve the problem. He lay down on the chair, stared at the ceiling silently, and began to doubt life.
"By this point, you should know what to do next."
After a while, the excited eyes of the small round face were blurred into slits.
Lu Tianrui grabbed the manuscript paper from the table and looked over it impatiently. However, the next second, he began to doubt his life.
Xu Chuan stared at the two questions. The knowledge points required by the two questions could all be applied to physics.
"Give me the answer tomorrow."
"Brother Chuan, tell me about your analytic geometry problem-solving ideas, and how to find the limit. Can it also be done using integrals?"
A question that he couldn't find a way to solve in a short period of time was actually solved in Xu Chuan's hands?
Was he originally engaged in physics or mathematics?
The hour and a half of evening self-study passed quickly. Gong Rihui collected the answers on time and looked through them one by one.
"I understand! Brother Chuan!"
"It's okay. It should be possible to solve it."
"Lu Tianrui, where did your idea of using definite integrals to find the limit come from? What you learned was neither fish nor fowl! And you did it all wrong! The more you learn, the more you fall back! If this continues, are you going to participate in a p-number competition?"
"Also, Xu Chuan, sit in that seat and don't stay around him. He will lead bad people to me as soon as he comes."
Suddenly, Gong Rihui pointed his finger at Xu Chuan, pointed angrily at the seat on the other side of the classroom, and asked him to sit there.
This kid has led Lu Tianrui to bad things within one day of his arrival. If he works hard for a few more days, Lu Tianrui won't even have to participate in IMO.
Xu Chuan looked innocent, turned to look at the fat man next to him, and silently changed his position.