After Fang Chao finished the first logical and math problem, he breathed a sigh of relief, put the pen aside first, and shook his hand at the same time, not rushing to do the second problem.

He came to the life coach and took a bottle of mineral water from Baisui Mountain and dried half a bottle, and then took out a drawing paper to wipe the sweat on his face and neck, and by the way, he took a pack of Genji spicy slices and tore them open and ate them, it tasted good and delicious, at a time when everyone was immersed in the ocean of mathematics, this pack of spicy strips gave Fang Chao a lot of warmth, and made him sweat profusely, and his mouth made a 'huhu' sound.

"Cool!!"

So he poured a whole bottle of the hundred-year-old mountain down.

Lin Teng, a classmate, doesn't know how to study usually, and he is not particularly outstanding in learning, but for snacks, he is really impeccable, so he rushed to choose a pack of spicy strips, his friend, Fang Chao will hand it over in the future!

"I don't want to do the question well, but I came here to eat spicy noodles...... Aren't you afraid to have an impact on the exam? ”

A mentor came to Fang Chao's side and stared at him, looking at his appearance, he couldn't help but speak.

When has this been, and I still have the heart to eat spicy noodles here.

Fang Chao subconsciously replied, "Completed the first question, didn't it take me almost fifty minutes, I just came to the rest area to rest for a while and eat something to replenish my strength, teacher, you don't know, this first question is simply perverted, I usually do a math problem The most complicated thing is less than half an hour, this time the first question trapped me for fifty minutes, the battlefield of the national decision is really much more cruel than I imagined, I don't know if anyone has already solved the two questions." ”

"Did it take you fifty minutes to finish the first question?"

This tutor was a little surprised, before the question came out, they didn't know about it, basically all the news was blocked, only when the test paper was sent down, they also got a share, but in the face of the question of this national decision, even they couldn't get it in just fifty minutes, this kid ......

You know, many of the tutors are actually college mathematics professors, and they don't know how much better than these high school students, although they can solve this problem, but they can't do it in only 50 minutes.

Isn't the student in front of you a blind man? I'll have to take a look later.

He still didn't believe it, there really was someone who could solve the first question in fifty minutes.

None of the questions on the national referendum are simple......

What do you think of the national decision?

After eating spicy strips and drinking mineral water, Fang Chao felt energetic again, and he wiped his hands clean before returning to his seat.

The second question of the national duel begins.

The second question of the national decision is as follows: find the maximum and minimum values of S=(a+b)(b+c)(c+d)(e+a) for the real numbers (a, b, c, d, e) that satisfy a, b, c, d, e, ≥-1 and all a+b+c+d)(e+a).

This question is much less than the first question in terms of word count, but its difficulty is definitely not much easier than the first question.

That's where the beauty of math comes in, and it's hard to get you hooked.

Fang Chao finally found his sense of existence on the second question of the national decision.

I'll answer this question.

It's a bit complicated, but not too difficult.

Let me get you done!

Fang Chao took a deep breath, and then began to pick up the pen.

Solution: Find the maximum value of S first.

When a=b=4, c=d=e=-1, S=288, consider the case of S>0 below.

You might as well let a=max{a,b,c,d,e}, then a≥1, so a+b≥0,e+a≥0.

Therefore, a+b,b+c,c+d,d+e,e+a,e+a are all positive or two negative and three positive.

……

That is, the maximum value of S is 288.

Next, find the minimum value of S.

……

S≥-2*3^4=-162

So the minimum value of S is -512.

"Hmm, it's a little simple, it's boring, it's so easy, it only took me more than 20 minutes to complete this question......"

Fang Chao was a little disappointed, will the second question in the national finals be sauce purple? It makes people can't feel the challenge, who is the person who made the question, come out!

And the tutor who was secretly observing Fang Chao eating spicy strips earlier didn't know when he stood behind Fang Chao, he kept staring at the steps of solving the first question on Fang Chao's test paper, as a tutor, although he couldn't complete the steps, but he knew the answer, so when he saw that Fang Chao's final answer was the fourth, he knew that the other party basically got a score for this question, as long as there were no mistakes in the steps, then the 21 points were in hand.

So he began to slowly look down from Fang Chao's first train of thought.

"That's right."

"That's right."

"Not bad."

"Yes!"

It wasn't until after reading everything that he was secretly surprised, which province did this young man come from? Seems a bit strong......

It is not surprising that there are some special strong people in the national finals every year, but it is rare for such a question to be solved so quickly.

Fang Chao, FJ Province......

I think I've seen it on the list......

Freshman in high school?

Yes, it's a freshman in high school!

If it is other students, unless they are particularly strong, these tutors will remember, after all, there are nearly four hundred contestants, if they are not particularly awesome, it is difficult for people to remember, Fang Chao did not come to such a stage with the attitude of a strong man, he entered such a field as a freshman in high school, so it will make people remember his particularity at once.

A rare contestant in the first year of high school.

Soon, however, his pupils dilated, and he looked at Fang Chao with a shocked expression.

In just such a short period of time, he even solved the second question?

And......

steps

Answer!

Nima, it's all right.

it! It's only been less than twenty minutes, right? Have you completed the second question? This...... Perverted, right? Are you still human?

Have all the current high school freshmen reached this point?

The first question has already dealt a heavy blow to this tutor, and the quick answer to this second question has made this tutor collapse, this player does not look ordinarily strong, but surprisingly strong.

Perhaps he will be the strongest dark horse in this year's national finals.

In the case of completing two questions, 42 points are in hand, which can basically guarantee a smooth promotion.

Wait a minute, isn't this kid done?

What is he still doing now?

Is this the second way of solving the problem to solve this problem?

What do you think of the national final?

Is it so easy?

"!!"

The mentor subconsciously said a dirty word.