God-level Xueba system upgrades 999 seconds

Of course, all electronic devices are not allowed to be brought into the venue. Once discovered, they will be punished as cheating.

However, you can bring three reference materials.

Yes, IMO is an open-book meeting!
But if you think it's easy IMO, you'd be wrong.

IMO has a special rule, that is, every time you do a wrong question, not only will you not score, but you will also be deducted. That is to say, if you do not get 0 points for a question, you will win the championship. It may also fall to the last place.

This is IMO, this is the stage for the strong!

"Oh, interesting rules." Qin Luo smiled faintly, and turned to look at the surrounding crowd.

On the left, the face is solemn and the whole body is trembling.

On the right, looking pale and sweating profusely.

The front, uh - can't see clearly, but judging from his trembling body, he must be extremely nervous.

As for the back?Uh - still calm, although expressionless.

As for the members of the Huaxia team, Qin Luo looked curiously through the cracks.

Surprisingly, their faces were full of excitement, as if they were eager to try!

Lin Shanshan clenched her fists, her little heart beating uncontrollably: I didn't expect that I, Lin Shanshan, would one day stand on the IMO, earn, earn.

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Bring biscuits, milk, and three reference books, respectively "High School Mathematics Knowledge Encyclopedia", "Advanced Mathematical Formulas", "Three-year Olympic Games and Five-year Simulation"

That's right, Huaxia's manufacturers are so awesome!
After packing up the "props", Qin Luo walked into the examination room under the guidance of the staff.

The exam questions have been specially translated and replaced with Chinese.

When Qin Luo got the test paper, he suddenly found that the information he brought was useless.

The most useful things are bread and milk.

The former can fill the stomach, and the latter can quench the thirst.

1: Find all functions f:R→R, so that any real number X, Y has f({x}y)=f(x){f(y)}
Hehehe, Qin Luo's eyes flashed brightly, this question is quite interesting.He applied the knowledge of junior high school and high school to the extreme.

Qin Luo smiled slightly, looked up and looked around, and all he could see was the international common movement - biting the penholder!

Ha ha - horrible.

Countless people bit their pens and stayed in place, not to mention solving problems, they couldn't even move their pens.

Alas, masters are so lonely...

Qin Luo shook his head, picked up his pen and began to write. In just a few minutes, the answer was already on the paper.

Solution: let y=0, f(0)=f(x){f(0)}(*), if {f(0)}≠0, then f(x) is a constant function, Lin f (x)=c, substitute into c=c{c}
So c=0, or {c}=1, that is, 1≤C<2
If f{(0)}=0, it can be obtained from (*)...

……

... Substituting into the formula, it can be obtained that f(x)=0 or f(x)=c, 1≤c<2 all meet the requirements and are all solutions.

This is IMO, it feels quite relaxed, Qin Luo put down the pen in his hand, and looked at the people around who were "writing hard".

Thinking it was okay, he picked up the biscuit and gnawed it.

"Kats, Katz."

In this quiet classroom, the sound of cracking biscuits can be clearly heard.

what's the situation?What's that sound?
For a while, everyone turned their heads.

But in the next second, they were shocked, seeing Qin Luo holding the biscuit and sending it to his mouth.