My World is All Experience

解析：B=1/(1012-12)+1/(1022-22)+···+1/(1502-502)

=1/(100×102)+1/(100×104)+。。。+1/(100×200)

=（1/100）×（1/102+1/104+1/106+...+1/200)

=（1/200）×（1/51+1/52+1/53+...+1/100)

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A/B=200

T表示的是以点（0,7）为圆心，r为半径的圆及内部；S表示的是直线到直线cos2A＋xcosA＋y≥0的上方,而点（0,7）到直线的距离为d=(7+cos2A)/根号（1＋cosA平方）因此，rmin(d)=4根号2.

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A series of formulas came into view, and in just an instant, it attracted all his eyes and all eyes, and the expression that didn't care much gradually turned into a cautious color.

This test paper was chosen by him, and its difficulty is definitely not a joke. There are even many Olympiad questions in it, which makes the ordinary difficulty even higher.

This is also a decision he made after careful consideration. After all, there are still nearly [-] days before the college entrance examination. In this case, it is not the time to encourage, but to cool down. Simply put, it is a blow. Maybe some students will be able to go a step further.

And the results did achieve the preliminary results he wanted. This test paper was [-] points, and the best classmates were only [-] points. It can be said to be appalling.

Of course, this situation is also normal. Many of these questions are not difficult questions that must be taken in the college entrance examination. They are only possible. In fact, the probability of occurrence is not high, unless it is an arcane competition.

But what he saw at this time, on a piece of white paper, the dense formulas could easily solve a series of problems, and what shocked him was that almost every one of these problems was simple, and Not only that, there are even several ways to answer each question.

"This!"

"You can still answer like that!"

"Impossible. If this assumption is true, what's going on here?"

"By the way, there is another known condition, by the way, I never thought of it!"

Among the gradually glowing expressions, there are voices mixed in, and the expressions on the math teacher's face are constantly changing, either puzzled, surprised, or inconceivable.

Time continued to pass, even if it was just a blank sheet of paper, there were not many answers on it, but it was just this blank sheet of paper, which made him read it over and over again.

What surprised him even more was that some of them could be understood by him, and some of them could be verified even in difficult times, but there were some problem-solving methods that he didn't even have the qualifications to understand, which made him a little nervous. Living.

Even his mood was constantly ups and downs, and it took a long time for him to gradually calm down, so that his mood no longer fluctuated violently, but there was still a light in his eyes looking at this white paper.

"call!"

A long mouthful of turbid air protruded, and just as he was about to calm down his mind again, he suddenly caught a glimpse of the test paper next to him, causing his pupils to shrink violently.

Suppose the three points are A, B, and C, and the center of the sphere is O. From the meaning of the question, we know that ∠AOB=∠AOC=∠BOC=3?, ∴AB=BC=CA=R, ∴

The radius of the small circle is 3R, and the circumference of the small circle is 2??3R=4??R

......

Suppose the three points are A, B, and C, and the center of the sphere is O. From the meaning of the question, we know that ∠AOB=∠AOC=∠BOC=3?, ∴AB=BC=CA=R, ∴

The radius of the small circle is 3R, and the circumference of the small circle is 2??3R=4??R

Two paragraphs of the same question, the two places are exactly the same, the only difference is that one is on the white paper and the other is on the test paper, and what made his heart stop slightly is that these two paragraphs not only The content is exactly the same, and the handwriting is exactly the same, which undoubtedly means that it was written by a person's arm and also by a person.

"he!"

"how is this possible?"

Involuntarily, his eyes aimed at the row of names again, and when he saw the people he sighed before, the math teacher's mind that had just converged could no longer calm down at this moment, and even his voice could not help but blurt out.

This shock is even more shocking than when he just saw the formulas. He didn't think about it that much before, but at this time he found out that this was actually when the poor student who sighed wrote it. That mood swing was almost unprecedented, even beyond his imagination, making it difficult for this weather-beaten math teacher to accept at this moment.

This is not a questioning, this is not looking down, but an instinctive reaction after the inherent concept is impacted.

In his memory, what kind of student Jiang Chen was, and how clearly he was a math teacher, but what was going on now, how to explain it, and how to explain it.

Cheating, it's a joke, it's not possible to cheat at all.

Chapter [-] The math teacher was also scared (fourth more)

Don't say that this set of test papers has just come out, even he may be one of the first to get it. It is impossible to have a standard answer. Even if there is a standard answer, what is going on in front of you? Who is it? Is it not a joke to write a bunch of densely on the white paper, but there is almost nothing to fill in the test paper.

As for whether it was made by this student, it is also very simple. If you compare the handwriting carefully, you can find the problem. After all, everyone's handwriting is different, so you can naturally find the difference.

And obviously, even after careful comparison, he has to admit that this blank piece of paper and this test paper really came from the same hand.

"Could it be, he!"

There was a murmured voice, and there was an unbelievable color in it. For him at this time, it seemed that he had to accept this answer. This student was indeed a top student.

The so-called poor student is probably the result of the other party pretending to be a pig and eating a tiger, otherwise the situation in front of him would not be explained at all.

Although even this kind of explanation is actually untenable, at this moment, as a math teacher, he can only think so. After all, as a math teacher, he knows very well that the improvement of mathematics is not a one-off time. It may only take effort to increase from [-] points to [-] points, but it is impossible to increase from [-] to [-] points to [-] points, at least in a short period of time.

The only explanation is that Jiang Chen has been hiding his clumsiness, not taking the exam seriously, or even perfunctory at all. In this way, everything makes sense.

"Jiang Chen!"

Chewing on the name, the figure of the math teacher also got up at this moment, and at the same time, the figure hesitated and walked out of the office. Although the idea was probably basically a reality, he still needed some more verification.

He pays attention to logic, and his ideas seem to have a good explanation, but there are too many things that don't make sense. He needs more verification. The best way is to find the student to verify it. In fact, he knows .

However, when the math teacher stepped forward, he realized that the closing time for the fourth class in the afternoon had already arrived, and there was no one else in the classroom. Obviously, he seemed to be silent. All the formulas on the white paper were caught in it, which made his expression stunned, but in the end he did not choose to leave, but walked into the classroom.