Xueba, I beg you to go and escort him quickly!

"Isn't it just updated this season?"

"???"

"Why is it so easy for him to score? I've lost my shadow! Woooooo..."

"What the hell! I can't compare to studying and studying. Playing games, I was also tortured by blood!"

"Xu Heng, this is a 360-degree crush without dead ends!"

This side is still talking.

Someone came to the group again and announced, "Xu Heng is the king!"

Everyone, "..."

"Get out of the group! Get out of the group! Get out of the group!"

"Whooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo"

Xu Heng's game just ended, he stopped playing...  

Pick up the phone, click into the Q group, and then, "?"

Xu Heng asked, "Are you going to quit the group?"

Everyone was stunned, "No, no, no! How could it be possible to quit the group!"

"Xu Heng, please take me with you!"

Xu Heng, "I don't play anymore, I don't have time, I'm going on vacation!"

Everyone, "???"

"Don't you have more time when you're on vacation?"

Xu Heng, "It's a holiday, I have to go home, I have a lot of things to do, and I don't have time!"

"Stop talking, I'm going back to the dormitory to pack my things! It's time to prepare for winter vacation!"

Yue Pingting's exam is over.

Xu Heng packed his things and went directly to the girls' dormitory.

When he moved to the dormitory before, the dormitory manager let him in, but this time he was on vacation, he was naturally unimpeded.

After helping Yue Pingting pack up her things.

It just so happened that Yue's father came to pick them up by car.

After putting all the luggage away, Dad Yue drove slowly.

Because it was snowing, the road was very slippery and the car drove slowly.

in the car.Yue Pingting was very excited.

"Xu Heng! You don't know, I have done a lot of questions you gave me! Similar! I can almost write the answer directly! But to be on the safe side, I will calculate it step by step!"

Xu Heng smiled, "You still lack self-confidence."

Yue Pingting suddenly became mysterious, and moved closer to Xu Heng, "I suddenly noticed something, Xu Heng, tell me the truth..."

Xu Heng, "?"

Yue Pingting, "If my guess is right...Xu Heng, did you participate in our final exam? Otherwise, why wouldn't the school let you take the exam!"

"Also, in the test paper you gave me, there are really many questions that are similar to those of this final exam, including mathematics, physics, chemistry, and biology."

"I'm so embarrassed."

Xu Heng, "Ah... Really not! You think too much! You really think too much! How can I have time to write a paper?"

Yue Pingting didn't believe it, "You have been out for the Math Olympiad for so many days, just take one day at random!"

"Otherwise, why did the school let you not take the exam!"

"What are you talking about so as not to hit us! This reason is too nonsense!"

Even Father Yue agreed, "That's right, it's not a big deal, Xu Heng, just admit it!"

"Although there are rules that can't be said, but... For you, the final exam is over! It doesn't matter!"

Xu Heng sighed, "It's really not me! Uncle, if Pingting doesn't believe me, you should believe me too!"

Father Yue thought about it carefully, "I still choose to trust my daughter this time!"

Xu Heng, "%￥#￥..."

Yue Pingting looked at Xu Heng seriously, "Xu Heng, isn't it very good for you to do this...you are because of me..."

Xu Heng rolled his eyes at Yue Pingting, "Don't make trouble! This final exam is the city's joint exam, and the city's test papers are issued by the city. Tell me, there are so many people taking the exam together, can you find me?"

Yue Pingting, "But you also made a question for the national Mathematical Olympiad!"

Xu Heng, "Uh..."

From Yue Pingting's point of view, it must be because Xu Heng passed the test paper, that's why he was rejected for the final exam. That's why he gave himself some questions similar to the final exam.

Yue Pingting felt that Xu Heng had made a small fuss about her.

Xu Heng, "Let's take a step back, even if I really participate in the examination papers, can I still pass every subject?"

Yue Pingting scratched the back of her head, "But it's true that you gave me questions, and I encountered them in every exam! That's right! There's also composition!"

"Especially composition!"

I've always wanted to talk to you face to face, but I haven't seen your people these days!

Xu Heng, "Eh... Didn't it tell you to go back to the dormitory early because of the snow?"

Yue Pingting, "%￥##..."

"I don't want to entangle you with this. I mainly want to talk to you about the composition! Do you know that among the few composition cases you showed me, I really passed the exam this year!"

"This, you can't quibble!"

Xu Heng, "???"

Xu Heng really couldn't argue with his mouth, even if he jumped into the Yellow River, he wouldn't be able to clear it up.

Yue Pingting, "Don't pretend you don't know, it's the composition material for the ladder."

Xu Heng, "Um...which one!"

Yue Pingting rolled her eyes, "You pretend! You still pretend!"

Xu Heng really doesn't remember...

After telling Yue Pingting, he forgot.

After all, these things are too childish for him.

Take it out and talk about it, it's at your fingertips, and you don't need to remember it at all.

"So, which one is it?".

Chapter 228

"It's the one with the ladder!"

Probably:

A work ladder sits in the corner of a company workshop.

In order to prevent the ladder from falling down and hurting people, the staff specially wrote a banner beside it "Be careful".

No one paid much attention to this matter. Several years have passed, and there has been no incident of a ladder falling down and hurting anyone.

Once, a client came to discuss cooperation matters. He noticed the banner and stopped for a long time, and finally suggested that the banner should be changed to "Please put the ladder horizontally when not in use".

Yue Pingting, "It's not that you told me that two different prompts for the same purpose have different effects..."

"Usually we are always used to talking about general principles, that is, to pay attention to safety, this, but please put the ladder horizontally when not in use later, and this is implemented in the specific things to be done..."

"..."

"Prevention before it happens..."

"You told me these things, do you remember?"

Xu Heng nodded, feeling somewhat impressed.

"So... this composition was tested in the Chinese final exam?"

Yue Pingting nodded seriously.

Xu Heng, "Hiss... what a coincidence!"

Yue Pingting pouted, "Just pretend!"

Xu Heng, "Hey..."

I really didn't pretend!

never mind!

Since the explanation cannot be explained clearly, then there is no explanation.

Xu Heng looked out of the window, which was completely covered in silver.

"Oh, by the way, Xu Heng, let me ask you a question!"

"Last math problem for the final exam."

"I wrote it down in the notebook!"

Since being "specially trained" by Xu Heng, Yue Pingting's enthusiasm for learning has become higher and higher.

When she encountered a problem she didn't know, she relied on her memory and the help of her classmates to solve the problem.

Xu Heng came back to his senses and looked at the question.

His hanging heart fell down.

Fortunately, this question is not something he talked about...

topic:

Let M be a set composed of some positive integers, the first item of the sequence {an} is a1=1, and the sum of the first n items is Sn. It is known that 18 pairs of arbitrary integers k∈M, when the integer n>k, S(n+k )+S(nk)=2(Sn+Sk) are all established.

（1）设M={1}，a2=2，求a5的值；

(2) Set M={3,4}, find the general term formula of the sequence {an}.

Father Yue watched through the rearview mirror that Yue Pingting and Xu Heng were discussing study so seriously.

He was very pleased.

He has always been very familiar with Yue Pingting's studies!

If it weren't for Xu Heng, Yue Pingting might never have had such initiative in learning!

He is very grateful to Xu Heng!

From the heart!

In Yue's father's eyes, it was Xu Heng who gave Yue Pingting a chance to be reborn!

Xu Heng looked at the question and said bluntly, "This test is about the recursive simplification and evaluation of number sequences, as well as the synthesis of number sequences and functions."

He always hits the nail on the head!

“由集合M的元素只有一个1，得到k=1，所以当n大于1即n大于等于2时，S（n+1）+S（n﹣1）=2（Sn+S1）都成立。”

"After the transformation, use S(n+1)-Sn=a(n+1) and a1=1 to simplify, and when n is greater than or equal to 2, this sequence is an arithmetic sequence after removing the first item."

“根据第2项的值和确定出的等差写出等差数列的通项公式，因为5大于2，所以把n=5代入通项公式即可求出第5项的值。”

"This question is not difficult for you, is it?"

Yue Pingting nodded with a smile, "You're thinking the same way as I am, I'm right, hehehe! What about the second question?"

indeed!

The second question of this question is relatively more difficult.