Soon, the math teacher, Mr. Zhen, was invited over.

Mr. Zhen is not only a mathematics teacher, but also the director of mathematics in the entire Zhongnan No. 1 Middle School, it is not easy to become a teacher in a provincial key high school like Zhongnan No. 1 Middle School, and he is also the director of mathematics, which is enough to show his ability, and he is quite famous in the education circle of Zhongnan City.

Knowing the situation, Teacher Zhen agreed, because he also wanted to know if Qin Wudao had relied on his own strength to get a nearly full score in the math test paper.

It is not an ordinary difficulty to know the mathematics paper of the second mock test.

Teacher Zhen quickly wrote down a difficult problem on the blackboard: "Knowing that a, b are real numbers, the functions f(x)=x^3+ax, g(x)=x^2+bx, f'(x) and g'(x) are derivatives of f(x), g(x), if f'(x)g'(x)≥0 is constant on interval I, then f(x) and g(x) are monotonicity consistent on interval I, now a<0, and a≠b, if the functions f(x) and g(x) are monotonicity consistent on the open interval with a, b as the endpoint, find |The maximum value of a-b|. ”

As soon as they saw the question, all the students subconsciously answered it on a blank piece of paper.

Zhang Yue is the same.

The same is true of top students like Li Ziwei and Mu Tianyan.

Only Qin Wudao looked at the topic lightly and remained motionless.

After about ten minutes passed, Qin Wudao was still motionless at the table.

Li Ziwei, Mu Tianyan and a few top students who were relatively good at mathematics stopped, obviously and the solution came out.

Zhang Yue also raised his hand at this time and spoke: "Teacher, I have solved the answer." ”

He also submitted the steps and answers to the problem.

The math teacher looked at it for a moment, nodded slightly, and obviously Zhang Yue had solved it.

He immediately looked at Qin Wudao and said, "What about you, classmate Qin?"

Qin Wudao spoke: "I have also solved the answer." ”

Everyone was stunned, you didn't have an answer at all, how do you know the answer.

The math teacher also frowned slightly and said, "What's the answer?"

“1/3！”

Everyone was stunned, and the math teacher was even more surprised: "How did you solve it?" ”

Obviously, Qin Wudao's answer was correct.

It's just that Qin Wudao didn't answer on paper from the beginning, it is impossible to know the answer, could it be that he has read the answer?

Many students were puzzled and thought that this idea was the most likely.

Zhang Yue stood up and said, "Qin Wudao, you have read the answer again." ”

Qin Wudao sneered: "The question was randomly selected by the math teacher, I didn't know in advance, do you suspect that Teacher Zhen is colluding with me?"

Zhang Yue's expression changed, and he hurriedly said: "I don't dare to doubt Teacher Zhen, but how do you know the answer, you haven't analyzed it yet." ”

Qin Wudao said lightly: "Because I analyzed it in my mind." ”

"Impossible!"

Everyone doesn't believe it, and in the mind of the analysis, is that still a person?

Qin Wudao stood up, walked directly to the blackboard, picked up the chalk and wrote, and explained: "This problem is first to find a derivative, and the solution is f'(x)=3x^2+a g'(x)=2x+b

Then, from the condition, we can see that in the interval, there is (3x^2+a)(2x+b)≥0. ”

"Then draw the figure f'(x)=3x^2+a, which is a parabola with a vertex of (0,a) and an opening pointing upward. ”

"Again, g'(x)=2x+b, which is a straight line. ”

"Because the question is not given a big A or B, the question is a little more complicated. ”

"There are two cases, first assume that b is greater than a, so the interval is (a, b), according to the image, we can know that the intersection of the line and the x-axis is (-b/2, 0), if b is greater than 0, so b is greater than -b/2, then on the interval (-b/2, 0), g'(x) is greater than 0, and f'(x) is less than 0, so b cannot be greater than 0. ”

"When b is not greater than 0, the intersection point (-b/2, 0) is on the right side of the y-axis, or on the y-axis (b=0), then there is g'(x) in the interval (a, b) is always less than or equal to 0, then it shows that f'(x) is also constant less than or equal to 0 on (a, b), through the image, it can be found that when x is less than -√-a/3, f'(x) is greater than 0, so there is a greater than or equal to -√-a/3, and the solution a is greater than or equal to -1/3. 1/3,0), b is in the range of (a,0], so there is a maximum value of |a-b|1/3. ”

"When b is less than a, then b is less than 0, and the graph is the same as above, and the solution a is greater than or equal to -1/3, and b is greater than or equal to -√-a/3, and the result is unsolvable. ”

Zhang Yue couldn't help but ask: "Why is it that when x is less than -√-a/3, f'(x) is greater than 0, so a should be greater than or equal to -√-a/3?"

Qin Wudao explained: "Let's talk about the second one first, since the intersection of g'(x)=2x+b and the x-axis is (-b/2,0), it can be seen from the image that when x is greater than -b/2, g'(x) is greater than 0, and then let b be greater than 0, then there is -b/2 less than 0 and less than b, which means that in the interval of (-b/2,0), g'(x) is greater than 0, and from the image, it can be seen that in (-√-a/ 3,0), f'(x) is less than 0, which means that no matter what the relationship between a and b is, there must be an interval less than 0, g'(x) is greater than 0, and f'(x) is less than 0, so b must not be greater than 0. That's why the interval is (a, b). ”

"First, since it has been proved above that b is less than or equal to 0, it means that -b/2 is greater than or equal to b, and it can be seen from the image that in the interval (a, b), g'(x) is always less than or equal to 0, then there must be in (a, b), f'(x) is also always less than or equal to 0, so a must be greater than or equal to -√-a/3, because as long as a is less than -√-a/3, it means that on the interval (a, b), the x value can be taken, so that f'(x) is greater than 0. ”

"Because the size of a and b is not given in the question, when b is less than a, the specific value cannot be obtained, but the maximum value can be proved to be less than 1/3 through discussion. ResultsWhen the two conditions are combined, the maximum value is 1/3. ”

Although it was only one question, all the students basically believed that Qin Wudao really relied on his own strength to solve it.

A person who can solve the answers to big math problems in his mind, and on the basis of not giving the size of a and b, can still calculate how powerful it is, there is no need to say more.

Teacher Zhen's gaze at Qin Wudao was full of appreciation, he was a genius!

Zhang Yue's face changed and changed, and he would never allow this to happen, so he asked the teacher to continue to ask a few big questions.

He wants to overpower Qin Wudao in the big question behind.

He didn't believe that Qin Wudao was really that powerful.

However, in the follow-up questions, Qin Wudao quickly answered them before Zhang Yue had half of the steps.

Even, this gamble attracted the attention of teachers of other subjects, especially when it came to Qin Wudao, the first student of the new grade who jumped up, these teachers were also very suspicious of his strength, even if there was not the slightest evidence of it, but they were also quite skeptical and participated.

However, whether it is English, Chinese, or comprehensive, the teachers of each subject ask questions, and Qin Wudao answers them all quickly and perfectly.

Looking at Zhang Yue, whose face was becoming more and more blue, Qin Wudao sneered, what kind of person is he, a generation of undefeated gods of war, not only has amazing combat power, but also wisdom, otherwise how could he dominate the world in his previous life, making all the great powers bow down, do you really think that he is simple-minded?

The so-called mathematics is just ordinary in his eyes, if he is not too lazy to waste time to study, otherwise it is not impossible to solve the so-called mathematical conjecture, and how can it be compared with a mere Zhang Yue.

Qin Wudao looked at Zhang Yue and said coldly: "You lost." ”

Zhang Yue's face was ugly, but he had to admit: "Yes, I lost, I admit that you didn't cheat." ”

After that, he was going to go back, but Qin Wudao grabbed him with one hand and raised his eyebrows: "That's all?"

Zhang Yue panicked and said, "What else do you want?"

"I am willing to lose the bet, lie on the ground and learn that the dog barks three times!" Qin Wudao said lightly.

Zhang Yue's face changed color on the spot, and he said hatefully: "Qin Wudao, don't be too ruthless, stop in moderation, and see each other in the future." ”

Qin Wudao sneered: "I originally planned to do this, but you want to force yourself, you can't blame me." Get down and learn to bark, or don't blame me for taking it personally. ”

Feeling the sharp pain coming from the place where his arm was caught, as if his arm was about to be broken, Zhang Yue's color changed.

He gritted his teeth and hurriedly looked at the teacher, hoping that the teacher would come forward.

But Mr. Zhen admired Qin Wudao quite a lot after this incident, and he was able to solve the answer with mental arithmetic, which was definitely a material that could be made.

And after understanding, I knew that Zhang Yue had provoked this matter, so naturally I would not help.

The head teacher, Li Shi, could only frown slightly, and said, "Wudao classmate, this matter-"

He didn't want his classmates to make trouble like this, after all, everyone was a classmate.

Qin Wudao said indifferently: "Teacher, you can also see that it is not that I am willing, but Zhang Yue has questioned me again and again, betting with me, and now that I have lost, I am naturally willing to gamble and lose, otherwise it will be spread out, and everyone in the entire Zhongnan No. 1 Middle School will think that I am a bully." ”

Li Shi sighed and walked out of the classroom, not wanting to see that scene happen.

Teachers from other subjects have also left.

Zhang Yue's face turned white on the spot, and he really wanted to bark in front of the whole class, and his face was lost.

"Qin Wudao, do you really want to be so ruthless?" Zhang Yue was still unwilling.

"Get down. ”

Qin Wudao was too lazy to talk nonsense, and pressed one hand on his shoulder, slightly harder.

Bang –

Zhang Yue fell to the ground uncontrollably, and was about to stand up angrily, but Qin Wudao's foot stretched out, pressed the volley on the top of his head, and said coldly: "If you don't fulfill your promise today, I will take action myself, but I can tell you that if I make a move, you will not just lie down and learn to bark." ”

There is no threat in the words.

Zhang Yue's face changed and changed, knowing that Qin Wudao's force value was very perverted, and it was rumored that even Xiang Rong and Zeng Jianneng were not opponents in the taekwondo gym, and if he resisted, he would only ask for trouble.

As a last resort, I had to learn to bark in humiliation: "Wangwang-"

"Remember not to provoke me next time you have nothing to do, you can't afford to mess with me. Qin Wudao said indifferently, with a sunny and handsome face, he had more than three points of evil charm, but he was even more handsome and eye-catching, which made many girls quite tempted.

Li Ziwei looked at him deeply.

After Qin Wudao left, Zhang Yue stood up with an ugly face and returned to his table.

This time, he lost face.

The whole class looked at Qin Wudao and finally accepted the fact that he had indeed scored 719 points in the test with his own strength, but they also seemed to see it, because of Qin Wudao's results, this time I am afraid that it will cause a big shock to the whole school!