The love of functions and derivatives

There is a knife next to the function, and there is black blood on the knife, which is obviously a murder weapon. The messy trampled and ground blood on the ground indicates a thrilling fight. There is also a strange man dressed as a deliveryman, with blood on his clothes Didi, wearing a helmet, stood aside and looked down at the function, muttering to himself, wondering: "Why is he still angry?"

The takeaway guy is probably the murderer.

Then why didn't he escape?

Derivative immediately called the hospital, but he didn't expect to be able to get through and have time to describe the situation of the function. Surprisingly, the takeaway boy didn't stop Derivative, but shook his head and smiled, "Don't struggle!" Oh, you are a step late, he was like this three or ten minutes ago, besides, I was in the lying position when I stabbed, and I pulled out the knife on purpose at the same time, based on my common sense, you can’t save him .”

Derivative's expression was a little weird when he heard the words, and a trace of surprise crossed his face, which soon disappeared. He frowned and asked, "Who are you? Why did you do something to him?"

"Because the function is supposed to die." The delivery boy smiled fiercely, "He should disappear from this world forever."

There was a vibrating sound from the mobile phone, and the call was connected. Function had no time to care about the takeaway boy. He was secretly vigilant, and said to the phone, "Hello, my friend was stabbed vertically in the left chest with a fruit knife. We have a Room [-], Unit [-], Building [-] in the community."

The other party asked: "What blood type?"

"The blood type is—" Derivative thought for a while, "Hero ink."

In fact, the derivative has been worried that the delivery boy will stop his call, but the delivery boy has been watching the whole process with cold eyes.

Was he too confident that the function would do what he said it would?

But... Existence as defined by mathematics is eternal life.

A cloud of doubts lingered in Derivative's mind, so he didn't think about it for the time being, and took a few steps in the direction of the delivery boy.

Derivative's height is 1.9 meters, which is an oppressive advantage for the 1.7-meter takeaway boy. "I advise you to stop and surrender to the police station. You don't have a knife now, you can't beat me."

"You're thinking wrong, I still have a knife." The takeaway boy pulled off the stickers of a certain takeaway vest, revealing the clothes inside - there is a concentric circle logo on the left chest, what pattern is on it, the outside Circles are numbers and English letters.He took out a knife from the interlayer of the takeaway clothes.

"But I don't want to kill you." The delivery boy said suddenly, "Do you still remember He Jun?"

Some fragmentary pictures buried deep in the memory emerged, filled with blood vessels and nerves, accompanied by the fear that would be triggered every time a certain environment was encountered, similar to the root of the disease left by the body.

The figure of the derivative froze in place.

The takeaway boy seemed to have expected the reaction of the derivative.

"Oh, I wanted to watch him lose his breath." The takeaway boy's disappointed tone was palpable, and at the same time, he broke free from the shadow of Derivative when Derivative lost his composure, "Then, goodbye!"

The next scene was like a nightmare of how many midnight derivatives were awakened by fear. A drop of hot liquid splashed on the face, and the derivative opened his eyes wide.