Chapter 6 The most suitable method

After receiving the test paper, Xu Yuan took a quick look at it and found that the knowledge content covered by the questions was slightly more difficult than what he had done before.

It should be the test paper that the school got from another province.

If he had taken this test at the beginning of the school year, he might not even have gotten a three-digit score.

But now?

It just makes him feel excited.

There is a sense of spiritual pleasure and satisfaction.

addicted to it.

"I hope to encounter interesting questions and not be disappointed."

He muttered to himself, then began to concentrate.

However, it is worth mentioning that when doing the previous multiple-choice questions, he used draft paper very rarely, as if he intentionally reduced manual calculations and relied solely on his brain to come up with the answers.

In his previous life, when he was preparing for the postgraduate entrance examination, he had specially trained his abilities in mathematical calculations, abstract thinking, and spatial imagination.

This is of great help in studying mathematics.

Now that he has replaced the new hardware, he will certainly not abandon these training methods.

On the contrary, the effect after use is quite significant.

In order to better improve these abilities, unless he encounters a difficult question, he will choose to calculate the answer in his mind.

And the speed of answering questions is not slow.

At the same time, Wang Qingtao, who was sitting on the podium, was also working on the test paper like everyone else.

He believes that only by doing it himself can he better explain it to students.

But if someone carefully observed Wang Qingtao at this time, they would find that he occasionally stopped writing, raised his eyes, and glanced towards where Xu Yuan was.

As a mathematics teacher and class teacher, Wang Qingtao would fulfill his responsibilities during the period no matter what the purpose was for registering Xu Yuan for the league and would never ignore it.

This was also the reason why he told Xu Yuan to come to him anytime if he had any questions that day.

But after a few days he was quite disappointed.

Xu Yuan never asked him any questions.

With many years of teaching experience, he does not think that mathematics is a subject that can be studied and improved on one's own.

Having someone to explain and guide you can often achieve twice the result with half the effort.

After Xu Yuan signed up for the league, he did work very hard and spent all his time reviewing mathematics, and he saw all of this.

But if you ask him to give an evaluation, it would only be two simple words.

Study hard.

It won't help the league.

Under this circumstance, his previous thoughts changed.

I feel that it is a bit of a luxury to let Xu Yuan take more than a month to face the reality.

This is especially true for a college entrance examination candidate who is about to take the three-year comprehensive exam.

Coincidentally, the school had just received a batch of high-quality test papers from other provinces, so he thought about organizing an exam.

As long as Xu Yuan's grades did not improve, they could use this as an excuse to persuade him to prepare for the college entrance examination and focus on the subjects in which he was weak.

Anyway, taking exams is normal for high school seniors.

"The difficulty of this test is much higher than the last time. I guess the scores of the class will not be very good."

When Wang Qingtao finished one of the big questions, his brows unconsciously frowned.

Show empathy to your students.

But he didn't think it was a bad thing. It could just add some pressure on them.

So that you don’t really think that you can rest easy just by getting into a key class.

As time passed, the only sounds in the classroom were the flipping of test papers and the pens scratching across paper.

The occasional coughs added to the atmosphere.

During the break, some students from other classes came over and saw what was going on inside through the window and left on their own accord.

It was not until the second half of the class that Wang Qingtao got up and moved around the classroom a few times.

He caught a glimpse of Xu Yuan frowning, and couldn't help but stop for a moment, his eyes falling on the paper.

"This solution is too complicated. There must be a more suitable one."

Xu Yuan didn't know that Wang Qingtao was standing next to him. His mind was focused on one of the big derivative questions.

His mind worked quickly. Derivatives were among the most difficult subjects in high school mathematics, but that didn't mean he was stumped.

It actually didn't take him long to solve the problem.

I just felt that there should be a more suitable way to solve the problem, so I thought about changing my thinking and solving it again.

Anyway, it’s not a good idea to hand in the paper early.

Turn to a new page of draft paper and review the question again.

“Given the function f(x)=xe（x∈…”

“Find the monotonic interval and extreme value of the function f(x);”

“若x1≠x2，且……证明x1+x2＞2。”

It is obvious that the question involves the problem of extreme point offset. The relatively simple first question is nothing more than monotonic interval differentiation.

The key is the proof that follows.

When he encountered similar types of multiple-choice questions in the previous section, he could use Lagrange's mean value theorem or Taylor's formula to quickly get the answer.

It is not applicable to large questions.

After all, high school examinations mainly test high school mathematics knowledge, and the questions will basically not go beyond the syllabus.

"The essence of this problem is that the speed increase and deceleration on the left and right sides of the extreme point are different, so we should start from this point."

Xu Yuan subconsciously turned the pen with his right hand, and as he focused on thinking, he had a clearer understanding of the problem. Just as he was about to try his new ideas to calculate, he suddenly noticed that the progress bar in his sight had risen sharply.

-

Task: Derivative Problem Solving

Subject: Mathematics

Progress: 30%
Result: Not completed
"The progress bar has increased so much. It turns out that the new idea is more suitable than the previous solution."

Faced with such positive feedback, he did not delay any further and started solving the problem immediately.

“f(1+x)＞f(1+x)”

"Constructor g = f(1+x)-f(1-x)"

……

“x2-1＞1-x1，证明x1+x2＞2”

-

Wang Qingtao would never have thought that Xu Yuan had reached the level of thinking of multiple solutions to find the best one. After turning around a few times, he found that he was still studying the same big question and simply thought that he was stumped.

He shook his head and walked towards the podium, with an increasingly regretful look on his face.

I was thinking of calling Xu Yuan to my office tomorrow to have a good talk about the math league.

Soon.

It was not even ten o'clock when Wang Qingtao ordered the papers to be collected.

The students in the first row once again took the lead in collecting the test papers from the students behind them one by one.

Maybe someone was not satisfied with his answer, and the classroom suddenly became noisy.

"It's time to collect the papers so soon, and I haven't finished the proof for the last big question yet."

“I just wrote a solution.”

"Whoever made the test paper is much more difficult than the last time."

"Who of you has proved that derivative? It's killing me."

The only thing that can comfort everyone a little is that today we have morning and evening self-study.

This time, Xu Yuan did not stay in the class to review. After handing in the test paper, he rushed to the dormitory building with Yang Bin, Wang Yongjie and others.

The exam just now naturally became the topic of discussion on the way.

"The math test was much more difficult this time. I was so focused on the first few questions that I didn't even have time to finish a big question."

"How are you two?"

Wang Yongjie usually talks a lot. He took the initiative to talk about his situation and then asked Xu Yuan and Yang Bin next to him.

His expression seemed to be filled with pain as he spoke.

Yang Bin spread his hands and said, "I'm about the same as you."

"I have finished writing them all." Xu Yuan took over the conversation and responded immediately.

When they were about to continue talking, a familiar figure just happened to pass by. It was Xie Qisheng, who won the third prize in the provincial mathematics league.

(End of this chapter)