Chapter 24 It looks like this year, No. 4 Middle School will have a top student
The moment Xu You saw the question, he found the solution.
"According to the condition a＜|a|, we can conclude that a is less than 0. The entire inequality is divided by a at the same time, the sign of the inequality changes, and the purpose of reducing the power can be achieved at the same time." Xu You thought quickly in his mind.
With this treatment, not only the absolute value of the entire inequality is removed, but also the power is reduced to a quadratic inequality.
Next, you can solve it using your high school knowledge.
In less than a minute, Xu You figured out the answer to the first question.
And this is the speed achieved when deep learning is not enabled.
This is not because of anything else, but because Xu You has done too many questions .
In just 20 minutes, Xu You finished the first eight fill-in-the-blank questions.
Even the difficulty of each question exceeds that of the final fill-in-the-blank question in the college entrance examination.
But for Xu You now, these are just basic questions.
The quick completion of the fill-in-the-blank questions left Xu You with an hour to answer the questions.
This will allow Xu You to have enough time to deal with the next three big questions.
The first big question is a problem about solving a triangle.
Compared to solving triangles in the college entrance examination, there is additional knowledge about vectors and basic inequalities.
But this level of difficulty was still too easy for Xu You.
In ten minutes, the first big question was easily solved.
The last two big questions are about functions and conic sections respectively.
Compared with the first big question, the difficulty has increased a lot.
But within half an hour, Xu You successfully made it.
I looked at the time and there were still 20 minutes left.
At this time, some students handed in their papers.
However, they had not finished answering the papers. They just knew that they could not finish them even if they just sat there, so they might as well hand in the papers early and go home early.
Xu You was not in a hurry to hand in the paper. After all, there was a second test to come and he couldn't leave.
After checking it carefully, Xu You handed in the paper on time.
After the first test, the candidates couldn't help but complain.
"I spent a long time on this first question. It looks like an inequality, but it's actually a set of three inequalities, with absolute values."
"Why are there no multiple-choice questions in the math competition? You can't even guess the answer!"
"I can't finish the test in 80 minutes. I only finished one and a half questions before the time was up."
Some students who were not well prepared for the competition were defeated by the first attempt and gave up the second attempt.
The second test hasn't started yet, but the number of candidates in the examination room is less than half of that in the first test.
During this period, Xu You did not communicate with any other candidates.
There were no classmates here that Xu You knew, and he had nothing to complain about the first try.
After all, the difficulty of these questions can only be described as average.
As long as you prepare carefully in advance, it is impossible to do it without any ideas.
It would be better to use these 20 minutes to have a good rest.
The second test in a while will be the real test.
20 minutes later, the second test began.
There are only 4 questions in the second test, but they are all complex and long questions.
It can be said that it is not easy to do any one of them right.
After taking a quick look at the four big questions, Xu You also discovered that the difficulty began to increase significantly.
The first question is to find the maximum value of an algebraic expression.
Xu You read the question carefully, looking for the starting point.
Xu You didn't have a clear idea at the beginning, so he started to deduce some conditions in the question.
But at a crucial step, Xu You came to a standstill.
"Yes, use the mean inequality!"
At this moment, this important inequality suddenly popped up in Xu You's mind.
The mean inequality, also known as the average value inequality or the mean inequality, is an important formula in mathematics.
In high school math, you only learn a small subset of them: basic inequalities.
But for Xu You who is preparing for the mathematics competition, such important knowledge must naturally be familiar to him.
"Using the property of Hn≤Gn≤An≤Qn to transform it, we can derive the maximum value of this algebraic expression!"
After some deductions, Xu You used this key property and successfully solved the whole problem.
…
Soon, 150 minutes passed.
During this period, many students gave up struggling and chose to hand in their papers with large blank spaces.
If it is a fill-in-the-blank question, if you don’t know the answer, at least you can write a random number on it.
But for a big question like this, if you don’t have any ideas, you really can’t even guess the answer.
The most you can do is write some related formulas and pray that the examiner will give you a few sympathetic marks.
At the moment before the bell rang, Xu You finally finished the process of writing the last big question.
"Phew~ That was close. I finally finished answering."
This time, Xu You didn't even have time to check.
However, for Xu You, being able to answer all four major questions in the second test was already very satisfying.
Xu You thought that his ideas were correct, but he didn't know if there were any other problems in the process.
The two invigilators were also discussing in a low voice after collecting the papers.
"The competition questions are indeed different. Many students from the Provincial Experimental School, No. 1 Middle School, and No. 2 Middle School left a lot of blank answers."
"Yes, this question is really not easy. My math score in the college entrance examination was only over 130, and I couldn't even understand many of the questions."
The two of them checked the name and test number on each test paper to see if there were any missed papers.
"Um?"
At this moment, they suddenly saw a very special test paper.
Not only is the handwriting beautiful and neat, but the process of each question is also fully written.
Although there are some traces of outlining, it is precisely this that reflects the candidate's thinking process when solving the problem.
"No. 4 Middle School...Xu You?"
Seeing the name of the school, No. 4 Middle School, both of them were a little surprised.
Although No. 4 Middle School is quite good in Shengcheng, it is far from being top-notch.
"Do these processes look correct?"
“Although I don’t understand it, it looks very powerful.”
"Just now I saw a boy answering the questions very seriously. He didn't even look up the whole time. This boy was quite charming when he was answering the questions seriously. He must be that boy."
"Looking at this paper, the score will probably not be low. If you really don't know how to do it, who would waste two and a half hours sitting here and writing nonsense?"
"That's true. It looks like No. 4 Middle School will have a top student this year."
This time, there was no friend like Hu Shucheng waiting outside for Xu You to check answers together.
Xu You had a casual meal outside and did not go home, but returned to school.
Although I had asked for a day off, I still had a high-level class to attend in the afternoon and couldn't delay it.
Xu You is now full of energy every day.
Even though he had just experienced a morning of intensive answering, Xu You still felt in good shape after resting for a while.
"Xu You, how did you do on the exam?"
Seeing Xu You coming back , Hu Shucheng hurried over to ask.
"Anyway, it's already been made, so I don't know if it's right or not."
Xu You felt pretty good about himself, but before the results came out, he couldn't guarantee how much he would score.
"Just finish your answer. Based on my understanding of you, it's basically fine. Hehe, you don't know that the students in the math competition sprint class cried because of their answers. Teacher Qin didn't even have a good lunch."
