Chapter 13: Raindrop experiment

　　 "Mom, discuss something with you?" Cheng Nuo graciously rubbed Jiang Lan's shoulders and said with a grin.
　　 "What's the matter? Let's talk!" Jiang Lan was in a pretty good mood, and smiled and nodded.
　　 "That...can you give me two hundred dollars?" Cheng Nuo rubbed his hands and said, "Isn't this about to take the college entrance examination? I want to buy some study materials."
　　 "Really? Didn't you buy enough last time?" Jiang Lan asked puzzledly.
　　 Speaking of this, Cheng Nuo has a toothache.
　　 Although Cheng Nuo's parents limit the promised consumption in terms of pocket money, they can learn more, but Cheng Nuo's parents are not stingy at all.
　　 Due to the times, Cheng Nuo's parents are not highly educated. Both are college graduates. So the two put all their expectations on Cheng Nuo.
　　 As long as they spend money on studies, Cheng Nuo’s parents don’t discount at all. It's even worse.
　　 Can you imagine Cheng Nuo's mood when he saw the bookshelf full of review materials?
　　 He was a little wondering if he was their own!
　　 "Oh, this time the teacher asked me to buy some materials." Cheng Nuo has practiced the skills to lie and not blush, heartbeat, no, not heart dry.
　　 Anyway, just get the money.
　　 Cheng Nuo is right in one thing. The reason why he asked Jiang Lan for money was indeed to buy some information. However, it is not a learning material.
　　 As for Cheng Nuo's slowly reviewing materials on the bookshelf, he may not be able to finish it by his grandchildren. Also buying review materials, Cheng Nuo didn't feel so painful.
　　 Two hundred dollars, Cheng Nuo had his own plan.
　　 Jiang Lan did not doubt the authenticity of Cheng Nuo's words. Since it was related to learning, Jiang Lan took out two hundred yuan from his wallet without hesitation and handed it to Cheng Nuo.
　　 "Take it. If the review materials are not enough, I will go to the bookstore another day."
　　 "No need, no need..." Cheng Nuo waved his hands profusely, "Enough, these are enough."
　　 "Okay, I'm going to study, you guys keep talking, keep talking."
　　 Cheng Nuo quickly terminated the topic and returned to the bedroom with the schoolbag.
　　 "The number of floors is 12, the height is 40.54 meters, the length is 62.48 meters, the width is 54.24 meters, it covers an area of ​​3,388.92 cubic meters, the number of households is 36, the brightness is 10..."
　　 "Height 175.87 cm, weight 85.24 kg, vital capacity 4002...... Brightness 2......"
　　 "Speed ​​54 km/h, weight 3214 kg...... Brightness 15......"
　　 On the balcony, Cheng Nuo was wearing a casual hooded jacket, lying on the railing and looking at the city in the night sky with abilities.
　　 Even under the dark night sky, even some things that one's eyes can't see can be transformed into data and transmitted to Cheng Nuo's brain. Let Cheng Nuo feel that the whole world is in control.
　　 Cheng Nuo opened his arms and embraced the world.
　　 Suddenly, a cool breeze blew in, and the cold wind poured in from Cheng Nuo's neckline.
　　 "Aye! It's cold, so cold!"
　　 Cheng Nuo quickly closed the window and returned to the house shivering with cold.
　　 "The wind speed is 8.7 meters per second, and the temperature is 8.2 degrees Celsius." His own eyes gave Cheng Nuo an accurate number.
　　 "Is it going to rain?" Cheng Nuo wrapped herself in a blanket and looked up at the moonless night sky outside.
　　 The air humidity is 92.41%.
　　 Seeing such a value, Cheng Nuo estimated that 80% of it is really going to rain.
　　 After half an hour, a spring rain fell from the sky as expected.
　　 "The volume is 0.05 ml, the weight is 0.051 g, and the speed is 8.52 m/s..."
　　"The volume is 0.06ml, the weight is 0.059g, and the speed is 9.54m/s..."
　　 "Volume..."
　　 Cheng Nuo was lying on the bed, using raindrops to measure how many sets of data he could collect at the same time.
　　 Cheng Nuo finally came up with the answer-100 groups.
　　 At least for now.
　　 Once this number was exceeded, Cheng Nuo's brain felt dizzy. Cheng Nuo was worried about what would happen, so he resisted the idea of ​​wanting to resist the dizziness and continue to increase the data collected.
　　 For the current Cheng Nuo, 100 sets of data can be collected at the same time, which is enough.
　　………………
　　 The next day, Qingcheng was baptized by a spring rain, and the lead bloom disappeared, and the city was filled with the fragrance of earth.
　　 As soon as he arrived in the classroom, Cheng Nuo met Old Tang's call.
　　 "Cheng Nuo, Old Tang is looking for you again." Jiang Qingqing was the one who passed the message.
　　 When saying this, Jiang Qingqing also gave Cheng Nuo a surprised look. What did Cheng Nuo commit? I was called by Old Tang to go to a class last night, do you want to go today?
　　 "Oh, Cheng Nuo, you are here, come here, come here first."
　　In the office, when Old Tang saw Cheng Nuo walk in, he smiled and waved to Cheng Nuo immediately.
　　 Uh... Cheng Nuo paused.
　　 Old Tang’s attitude is really a bit uncomfortable!
　　 "Teacher, are you looking for me?" It was still a familiar opening.
　　 "Come on, Cheng Nuo, take a look at this question." Old Tang continued to smile.
　　 Cheng Nuo continued to panic...
　　 "Look at this question, can you make it?" Cheng Nuo took the question from Old Tang. My heart is also silently complaining.
　　 Just let me do this question directly last night, let me do it twice!
　　 Even though he complained in his heart, Cheng Nuo picked up the question and looked at it.
"There are n≥2 line segments on the plane, where any two line segments cross, and no third line segment intersects at the same point. Geoff selects an end point on each line segment and places a frog on this end point, UU Reading www.uukanshu.com, the frog faces the other end, and Geoff will slap his hands n-1 times. Every time he slaps his hands, each frog immediately jumps to the next intersection of the line segment where it is. Will change the direction of the jump, Geoff’s wish is to be able to place the frogs appropriately so that no two frogs will fall on the same intersection at any time:
　　(A) Prove: If n is an odd number, Geoff can always achieve his wish.
　　(B) Prove: If n is an even number, Geoff cannot realize his wish. "
　　 It is definitely not a good question to make Tang call a difficult question.
　　 Cheng Nuo had no thoughts on the calculation side in his mind. He pulled a chair and sat on the table in front of Old Tang to solve it.
　　 Old Tang also watched Cheng Nuo's movements attentively.
　　 Yesterday, because Cheng Nuo didn't expect Cheng Nuo to make it, so I didn't focus on Cheng Nuo at all.
　　 Now he wants to see if Cheng Nuo has become as genius as he thought.
Cheng Nuo was writing and drawing on a blank piece of paper. Old Tang was like a student at this time, staring at every number Cheng Nuo wrote on the paper without blinking, and speculated that it was reasonable. Sex.
　　At this time, the other teachers in the math group also arrived one by one.
　　 Seeing Lao Tang Zheng staring at a student attentively to solve a problem, he smiled and asked aloud, "Old Tang, did this student make you angry again?"
　　 The teacher thought that the student should have made a very simple and naive mistake when doing the problem. Old Tang called him to the office and directed him to do the problem.
　　………………
　　Ps: The unit of brightness I use here is: sb (Xiti), and I will use this unit in the future.