Reborn Xueba, you don't really think that studying is difficult, do you?

【2：已经a,b,c,d均为正整数，且logab=3/2,logcd=5/4,若a-c=9,则b-d=……】

tsk tsk!
Good guy, this is really a good guy.

This is really difficult, and it feels like it really needs to grind everyone's IQ to the ground!

由题便可轻松得到a^3/2=b,c^5/4=d,从而a=(b/a)^2,c=(d/c)^4，因此ab,cd，又由于a-c=9，所以(b/a)^2-(d/c)^4。

即(b/a+d^2/c^2)(b/a-d^2/c^2)=9。

This equation must be solved by everyone, right?

You only need to do some oral calculations to get a=25, b=125, c=16, d=32.

So bd=93.

Next question.

The third question examines the area of ​​the triangle formed by the foci of the two ellipses and the points on the ellipses.

The fourth question examines the extreme value of dividing the number of elements and the sum of elements in the decimal system.

The fifth question examines the monotonicity of the function and the ratio of the size of the function in the monotonic interval.

Question [-] examines the definition of imaginary numbers...

……

The summary is two words, simple.

There is no difficulty at all, no pressure, and you don't even need to think. You can know the answer at a glance.

A series of eight fill-in-the-blank questions took an average of no more than 10 seconds for one question, and only 80 seconds for the eight questions, which is more than a minute.

"Hey, it's really boring!"

"Just such a question can be used in a competition. The teacher who produced the paper is too incompetent."

"It's not even as good as Teacher Li Daxian in the morning. Compared with Teacher Ge Tianxing, it's even worse."

"Any fill-in-the-blank questions that Mr. Ge Tianxing gives me on weekdays can kill this competition question countless times in seconds."

"Let's not say it's me, even the third and fourth child and Fatty Dali should be able to score [-] or [-] points in the exam, right?"

"Well, be conservative, a few squares should be fine, after all, they have made a lot of progress recently."

"Even if you are not a master of science, it should not be far away. It's just that you haven't passed the exam to prove it."

"It may be difficult for them to do this question, but there is not enough time, a total of three hours, a question can be solved in 1 minute, there is always a sign in 10 minutes, right?"

Lin Bei thought to himself that he was extremely disappointed with the competition papers.

Then, he looked at the last three answer questions, "I hope this answer question can be made more difficult!"

"Otherwise, the three-hour examination paper can be finished in less than 10 minutes. It would be really boring."

"Especially this is my first time, no matter what I have to stick to it for 10 minutes, let's have a good time?"

Lin Bei sighed, and looked at the ninth question, which was also the first answer question, and saw...

【9：3/2≤x≤5，证明不等式2√(x+1)+√(2x-3)+√(15-3x)≤2√19。】

Lin Bei: "%￥#@#￥%..."

My heart was full of ninety-nine for 30 seconds.

It wasn't because he thought the question was difficult, let alone that he couldn't understand the question, and it took a full 30 seconds.

But purely, he was completely disappointed.

Even, he was going to collapse.

Is it really necessary to put this kind of pediatric inequality in a competition?Or answer the first question?

但凡平日多看点儿书，多刷几道题，便该知道（a+b+c+d)^2=a^2+b^2+c^2+d^2+2(ab+ac+ad+bc+bd+cd)≤4(a^2+b^2+c^2+d^2)，因此a+b+c+d≤2√(a^2+b^2+c^2+d^2),当且仅当a=b=c=d时取等号。

Just set a=b=√(x+1).

c=√(2x-3).

d=√(15-3x).

Then substitute in, and the inequality is easily proved.

Need 1 minute?
Shouldn't it be necessary?

Lin Bei didn't count the time either, anyway, he wrote from the beginning to the end in one breath, and then looked directly at the next question.

Then it was another minute, and it was the next question, and then another minute, Lin Bei still wanted the next question.

But suddenly he stopped his hand and dropped his pen.

Don't ask why.

just because...

There are only three questions in total, and he has already finished them all. This paper is at the end, so there are no questions left!
Seeing this scene, Lin Bei felt indescribably lonely, and couldn't help but bow his head and sigh alone. This sigh is unexplainable. The free flying flowers are as light as a dream, and the boundless rain is as fine as sorrow.

Hey, why is the word worry so good?

Especially when he thought that he had waited for so long, but it ended like this in the end, Lin Bei really couldn't accept it.

Seeing this scene, a female invigilator teacher who was nearly forty years old came over immediately, and said with gentle concern: "Student, what about you? You seem to be very uncomfortable. Do you want to take a rest before sitting down? There is enough time Do not worry?"

It's worth mentioning.

This female teacher has been paying attention to Lin Bei for a long time, and even saw Lin Bei from the moment she walked in.

After all, with Lin Bei's good looks, he stands out from the crowd, and it's hard not to attract attention.

But what this female teacher never expected was that just a few minutes after the exam started, Lin Bei couldn't take it anymore. Seeing her sad face, her typical mentality was about to collapse!

In previous years' Mathematical Olympiad exams, there were many students who broke down in the middle of the exam, and even cried loudly.

Even though these students are all top students from various schools, they are all top students.

But top academics, if they haven't undergone special training, are really not good enough in front of the Mathematical Olympiad.

So generally speaking, it is not surprising that the teacher sees the sad face of the students halfway through the exam.

But at this moment, it's not half of the exam!

The three-hour exam time is less than 10 minutes now, no, no, no, it seems that only 5 minutes have passed.

Just 5 minutes into the exam, Lin Bei couldn't take it anymore, which, I have to say, surprised the teacher.

"Could it be that the grades of good-looking students are not good? But if the grades are not good, it is impossible for their school to let them participate in the preliminaries of the Olympiad?"

"Or is it that the papers for this preliminary round are too difficult, so difficult that this baby can't do a single question, so he behaved so uncomfortable, so painful, that he was about to collapse when the exam just started?"

The former is highly unlikely.

After all, those who can participate in the competition are all selected from various schools.

Therefore, Lin Bei's grades should still be acceptable.

It's just that the questions in this competition are too difficult, beyond the range of Lin Bei's strength, so the performance is so painful.

Thinking of this.

The teacher immediately reminded: "This student, it doesn't matter if you can't do it, as long as you do your best. After all, if you can't do it, others may not be able to do it."

"We must put our minds at ease. Don't worry. If you don't know this question, just move on to the next question. You should finish everything you can...Huh? You've already finished question 11?"

Conscience of heaven and earth, she originally just thought that Lin Bei looked good and had a good temperament, so he should be a good student.

So, I just want to make a point.

This is not considered a violation of examination room discipline.

After all, as an invigilator, it is also necessary to guide the students' mentality to prevent extreme problems.

However, before he finished speaking, he stopped abruptly.

just because...

She actually discovered a very incredible scene, that is, Lin Bei has finished the 11th question?

It seems that there are only 11 questions in total, right?
In just 5 minutes, 11 questions were completed. Is this funny?Still very funny?

She didn't think that Lin Bei could get all the 5 questions right in just 11 minutes, and she must have scribbled all over.

And this just proves that Lin Bei's state at the moment is not generally bad.

After all, just scribbling all over the exam and finishing 11 questions directly, isn't this typical self-defeating?
"This person is probably a contestant from the school below, that is to say, he looks very good. His grades may be okay in his school, but he is far from the top one. When he encounters this competition question, he immediately reveals his true colors, and then his mentality collapsed."

This is the teacher's subconscious perception of Lin Bei.

But when Lin Bei heard her words, he sighed and shook his head, "Teacher, you misunderstood me. I feel uncomfortable and anxious. It's not because the paper is too difficult, but because it's too easy."

"I really don't know who made the test paper. It doesn't feel fresh or challenging at all."

"It really feels like a waste of time!"

Female invigilator: "(д)b??"

What? ? ?

What did she just hear?
Lin Bei scribbled 5 questions in 11 minutes, but he actually thought the questions were too simple?
This is no longer a breakdown of the mentality, but that the brain is going crazy, and it just started talking nonsense?

But talking nonsense, he is still pretty handsome, should we send him to rest quickly... how about treatment in the infirmary?